diff --git a/Makefile b/Makefile
index 507e600..b97a66d 100644
--- a/Makefile
+++ b/Makefile
@@ -39,6 +39,10 @@ efm32prog:
 	cd '.\efm32\GNU ARM v7.2.1 - Debug' && $(MAKE) all
 	commander flash '.\efm32\GNU ARM v7.2.1 - Debug\EFM32.hex' -s 440121060
 
+efm32bootprog:
+	cd '.\efm32boot\GNU ARM v7.2.1 - Debug' && $(MAKE) all
+	commander flash '.\efm32boot\GNU ARM v7.2.1 - Debug\efm32boot.hex' -s 440121060
+
 $(name):  $(obj)
 	$(CC) $(LDFLAGS) -o $@ $(obj) $(LDFLAGS)
 
diff --git a/efm32/.cproject b/efm32/.cproject
index 0f9b67d..1c5ecb7 100644
--- a/efm32/.cproject
+++ b/efm32/.cproject
@@ -29,6 +29,14 @@
 					<folderInfo id="com.silabs.ss.tool.ide.arm.toolchain.gnu.cdt.debug#com.silabs.ss.tool.ide.arm.toolchain.gnu.cdt:7.2.1.20170904." name="/" resourcePath="">
 						<toolChain id="com.silabs.ide.si32.gcc.cdt.managedbuild.toolchain.exe.1911691633" name="Si32 GNU ARM" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.toolchain.exe">
 							<option id="com.silabs.ide.si32.gcc.cdt.managedbuild.toolchain.debug.level.50213284" name="Debug Level" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.toolchain.debug.level" value="com.silabs.ide.si32.gcc.cdt.managedbuild.toolchain.debug.level.default" valueType="enumerated"/>
+							<option id="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.usescript.567506607" name="Use custom linker script" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.usescript" value="false" valueType="boolean"/>
+							<option id="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.script.583769327" name="Linker Script:" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.script" value="C:\Users\conor\Desktop\u2f-one\efm32\boot\EFM32.ld" valueType="string"/>
+							<option id="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.overrideflash.89245522" name="Override default flash options" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.overrideflash" value="true" valueType="boolean"/>
+							<option id="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.overrideram.83367783" name="Override default RAM options" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.overrideram" value="true" valueType="boolean"/>
+							<option id="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.flashorigin.1326657156" name="ORIGIN" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.flashorigin" value="0x8000" valueType="string"/>
+							<option id="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.flashlength.1545864710" name="LENGTH" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.flashlength" value="0x38000" valueType="string"/>
+							<option id="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.ramorigin.428840301" name="ORIGIN" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.ramorigin" value="0x20000000" valueType="string"/>
+							<option id="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.ramlength.1809448749" name="LENGTH" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.ramlength" value="0x8000" valueType="string"/>
 							<targetPlatform binaryParser="org.eclipse.cdt.core.ELF;org.eclipse.cdt.core.GNU_ELF;com.silabs.ss.framework.debugger.core.BIN;com.silabs.ss.framework.debugger.core.HEX;com.silabs.ss.framework.debugger.core.S37;com.silabs.ss.framework.debugger.core.EBL;com.silabs.ss.framework.debugger.core.GBL" id="com.silabs.ide.si32.gcc.cdt.managedbuild.target.gnu.platform.base.1696251138" isAbstract="false" name="Debug Platform" osList="win32,linux,macosx" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.target.gnu.platform.base"/>
 							<builder buildPath="${workspace_loc:/EFM32}/GNU ARM v7.2.1 - Debug" id="com.silabs.ide.si32.gcc.cdt.managedbuild.target.gnu.builder.base.819523820" keepEnvironmentInBuildfile="false" managedBuildOn="true" name="Si32 GNU ARM Builder" parallelBuildOn="true" parallelizationNumber="optimal" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.target.gnu.builder.base">
 								<outputEntries>
@@ -218,7 +226,7 @@
 			<storageModule moduleId="org.eclipse.cdt.core.externalSettings"/>
 		</cconfiguration>
 	</storageModule>
-	<storageModule moduleId="com.silabs.ss.framework.ide.project.core.cpp" project.generation="74" projectCommon.boardIds="brd2500a:0.0.0" projectCommon.buildArtifactType="EXE" projectCommon.importModeId="COPY" projectCommon.partId="mcu.arm.efm32.pg1.efm32pg1b200f256gm48" projectCommon.sdkId="com.silabs.sdk.stack.super:1.1.1._310456152"/>
+	<storageModule moduleId="com.silabs.ss.framework.ide.project.core.cpp" project.generation="114" projectCommon.boardIds="brd2500a:0.0.0" projectCommon.buildArtifactType="EXE" projectCommon.importModeId="COPY" projectCommon.partId="mcu.arm.efm32.pg1.efm32pg1b200f256gm48" projectCommon.sdkId="com.silabs.sdk.stack.super:1.1.1._310456152"/>
 	<storageModule moduleId="cdtBuildSystem" version="4.0.0">
 		<project id="EFM32.com.silabs.ss.framework.ide.project.core.cdt.cdtMbsProjectType.1696568425" name="SLS CDT Project" projectType="com.silabs.ss.framework.ide.project.core.cdt.cdtMbsProjectType"/>
 	</storageModule>
diff --git a/efm32/EFM32.hwconf b/efm32/EFM32.hwconf
index cb9fa1c..9e376b8 100644
--- a/efm32/EFM32.hwconf
+++ b/efm32/EFM32.hwconf
@@ -57,6 +57,11 @@
     <property object="PD10" propertyId="ports.settings.pullup" value="Enabled"/>
     <property object="PF4" propertyId="ports.settings.pinmode" value="Push-pull"/>
     <property object="PF5" propertyId="ports.settings.pinmode" value="Push-pull"/>
+    <property object="PF6" propertyId="ports.settings.dout" value="1"/>
+    <property object="PF6" propertyId="ports.settings.filter" value="Enabled"/>
+    <property object="PF6" propertyId="ports.settings.pinmode" value="Input pull"/>
+    <property object="PF6" propertyId="ports.settings.pulldirection" value="Pullup"/>
+    <property object="PF6" propertyId="ports.settings.pullup" value="Enabled"/>
     <property object="PORTIO" propertyId="portio.usart0.enable.cts" value="Enabled"/>
     <property object="PORTIO" propertyId="portio.usart0.enable.rts" value="Enabled"/>
     <property object="PORTIO" propertyId="portio.usart0.enable.rx" value="Enabled"/>
diff --git a/efm32/src/app.h b/efm32/inc/app.h
similarity index 100%
rename from efm32/src/app.h
rename to efm32/inc/app.h
diff --git a/efm32/src/InitDevice.c b/efm32/src/InitDevice.c
index 7a921cb..12891f7 100644
--- a/efm32/src/InitDevice.c
+++ b/efm32/src/InitDevice.c
@@ -651,6 +651,9 @@ extern void PORTIO_enter_DefaultMode_from_RESET(void) {
 
 	/* Pin PF5 is configured to Push-pull */
 	GPIO_PinModeSet(gpioPortF, 5, gpioModePushPull, 0);
+
+	/* Pin PF6 is configured to Input enabled with pull-up */
+	GPIO_PinModeSet(gpioPortF, 6, gpioModeInputPull, 1);
 	// [Port F Configuration]$
 
 }
diff --git a/efm32/src/device.c b/efm32/src/device.c
index 603b44b..ff1bab2 100644
--- a/efm32/src/device.c
+++ b/efm32/src/device.c
@@ -32,7 +32,13 @@
 #define	STATE1_PAGE		126
 #define	STATE2_PAGE		127
 
+#define APPLICATION_START_ADDR	0x8000
+#define APPLICATION_START_PAGE	(0x8000/PAGE_SIZE)
 
+#define APPLICATION_END_ADDR	(PAGE_SIZE*125-4)		// NOT included in application
+#define APPLICATION_END_PAGE	(125)				// 125 is NOT included in application
+
+#define AUTH_WORD_ADDR          (PAGE_SIZE*125-4)
 
 static void init_atomic_counter()
 {
@@ -254,9 +260,6 @@ void init_adc()
 
 
 
-static uint8_t _STATE1[sizeof(AuthenticatorState)];
-static uint8_t _STATE2[sizeof(AuthenticatorState)];
-
 void authenticator_read_state(AuthenticatorState * state)
 {
 	uint32_t * ptr = PAGE_SIZE*STATE1_PAGE;
@@ -272,7 +275,6 @@ void authenticator_read_backup_state(AuthenticatorState * state )
 void authenticator_write_state(AuthenticatorState * state, int backup)
 {
     uint32_t * ptr;
-    int i;
     if (! backup)
     {
         ptr = PAGE_SIZE*STATE1_PAGE;
@@ -402,6 +404,104 @@ void device_init(void)
         buf[i] = adc_rng();
     }
     dump_hex(buf,sizeof(buf));
-
-
 }
+
+typedef enum
+{
+    BootWrite = 0x40,
+    BootDone = 0x41,
+    BootCheck = 0x42,
+    BootErase = 0x43,
+} WalletOperation;
+
+
+typedef struct {
+    uint8_t op;
+    uint8_t addr[3];
+    uint8_t tag[4];
+    uint8_t len;
+    uint8_t payload[255 - 9];
+} __attribute__((packed)) BootloaderReq;
+
+//#define APPLICATION_START_ADDR	0x8000
+//#define APPLICATION_START_PAGE	(0x8000/PAGE_SIZE)
+
+//#define APPLICATION_END_ADDR	(PAGE_SIZE*125-4)		// NOT included in application
+
+static void erase_application()
+{
+    int page;
+    uint32_t * ptrpage;
+    for(page = APPLICATION_START_PAGE; page < APPLICATION_END_PAGE; page++)
+    {
+        ptrpage = page * PAGE_SIZE;
+        MSC_ErasePage(ptrpage);
+    }
+}
+
+static void authorize_application()
+{
+    uint32_t zero = 0;
+    uint32_t * ptr;
+    ptr = AUTH_WORD_ADDR;
+    MSC_WriteWordFast(ptr,&zero, 4);
+}
+int bootloader_bridge(uint8_t klen, uint8_t * keyh)
+{
+    static int has_erased = 0;
+    BootloaderReq * req =  (BootloaderReq *  )keyh;
+    uint8_t payload[256];
+    /*printf("bootloader_bridge\n");*/
+    if (req->len > 255-9)
+    {
+        return CTAP1_ERR_INVALID_LENGTH;
+    }
+
+    memset(payload, 0xff, sizeof(payload));
+    memmove(payload, req->payload, req->len);
+
+    uint32_t addr = (*((uint32_t*)req->addr)) & 0xffffff;
+
+    uint32_t * ptr = addr;
+
+    switch(req->op){
+        case BootWrite:
+            /*printf("BootWrite 0x%08x\n", addr);*/
+            if (ptr < APPLICATION_START_ADDR || ptr >= APPLICATION_END_ADDR)
+            {
+                return CTAP2_ERR_NOT_ALLOWED;
+            }
+            if (!has_erased)
+            {
+                erase_application();
+                has_erased = 1;
+            }
+            MSC_WriteWordFast(ptr,payload, req->len + (req->len%4));
+            break;
+        case BootDone:
+            /*printf("BootDone\n");*/
+            authorize_application();
+            NVIC_SystemReset();
+            break;
+        case BootCheck:
+            /*printf("BootCheck\n");*/
+            return 0;
+            break;
+        case BootErase:
+            /*printf("BootErase\n");*/
+            erase_application();
+            return 0;
+            break;
+        default:
+            return CTAP1_ERR_INVALID_COMMAND;
+    }
+    return 0;
+}
+
+int is_authorized_to_boot()
+{
+    uint32_t * auth = AUTH_WORD_ADDR;
+    return *auth == 0;
+}
+
+
diff --git a/efm32boot/.cproject b/efm32boot/.cproject
index 41587a3..a6eb75c 100644
--- a/efm32boot/.cproject
+++ b/efm32boot/.cproject
@@ -29,6 +29,11 @@
 					<folderInfo id="com.silabs.ss.tool.ide.arm.toolchain.gnu.cdt.debug#com.silabs.ss.tool.ide.arm.toolchain.gnu.cdt:7.2.1.20170904." name="/" resourcePath="">
 						<toolChain id="com.silabs.ide.si32.gcc.cdt.managedbuild.toolchain.exe.930698941" name="Si32 GNU ARM" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.toolchain.exe">
 							<option id="com.silabs.ide.si32.gcc.cdt.managedbuild.toolchain.debug.level.2037798819" name="Debug Level" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.toolchain.debug.level" value="com.silabs.ide.si32.gcc.cdt.managedbuild.toolchain.debug.level.default" valueType="enumerated"/>
+							<option id="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.overrideflash.495029551" name="Override default flash options" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.overrideflash" value="true" valueType="boolean"/>
+							<option id="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.flashlength.2021030475" name="LENGTH" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.flashlength" value="0x8000" valueType="string"/>
+							<option id="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.overrideram.2020332041" name="Override default RAM options" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.overrideram" value="true" valueType="boolean"/>
+							<option id="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.ramorigin.2081162957" name="ORIGIN" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.ramorigin" value="0x20000000" valueType="string"/>
+							<option id="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.ramlength.1981650487" name="LENGTH" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.linker.ramlength" value="0x8000" valueType="string"/>
 							<targetPlatform binaryParser="org.eclipse.cdt.core.ELF;org.eclipse.cdt.core.GNU_ELF;com.silabs.ss.framework.debugger.core.BIN;com.silabs.ss.framework.debugger.core.HEX;com.silabs.ss.framework.debugger.core.S37;com.silabs.ss.framework.debugger.core.EBL;com.silabs.ss.framework.debugger.core.GBL" id="com.silabs.ide.si32.gcc.cdt.managedbuild.target.gnu.platform.base.613101530" isAbstract="false" name="Debug Platform" osList="win32,linux,macosx" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.target.gnu.platform.base"/>
 							<builder buildPath="${workspace_loc:/efm32boot}/GNU ARM v7.2.1 - Debug" id="com.silabs.ide.si32.gcc.cdt.managedbuild.target.gnu.builder.base.2113865201" keepEnvironmentInBuildfile="false" managedBuildOn="true" name="Si32 GNU ARM Builder" parallelBuildOn="true" parallelizationNumber="optimal" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.target.gnu.builder.base"/>
 							<tool id="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.compiler.base.981192541" name="GNU ARM C Compiler" superClass="com.silabs.ide.si32.gcc.cdt.managedbuild.tool.gnu.c.compiler.base">
@@ -91,9 +96,9 @@
 					</folderInfo>
 					<sourceEntries>
 						<entry excluding="crypto|fido2|efm32" flags="VALUE_WORKSPACE_PATH|RESOLVED" kind="sourcePath" name=""/>
-						<entry excluding="aes-gcm/|micro-ecc/examples/|micro-ecc/scripts/|micro-ecc/test/|tiny-AES-c/" flags="VALUE_WORKSPACE_PATH" kind="sourcePath" name="crypto"/>
-						<entry excluding=".settings/|CMSIS/|docs/|emlib/|GNU ARM v7.2.1 - Debug/|hw/|inc/|mbedtls/|sl_crypto/|src/.crypto.c.swp|src/.device.c.swp|src/app.h|src/main.c|.cproject|.project|EFM32.hwconf|Makefile|src/crypto.c" flags="VALUE_WORKSPACE_PATH" kind="sourcePath" name="efm32"/>
-						<entry excluding=".ctap_errors.h.swp|.ctap.c.swp|.ctap.h.swp|.main.c.swp|.storage.h.swp|.wallet.c.swp|.wallet.h.swp|crypto.c|main.c|ctap_parse.c|ctap.c" flags="VALUE_WORKSPACE_PATH" kind="sourcePath" name="fido2"/>
+						<entry excluding="aes-gcm/|micro-ecc/examples/|micro-ecc/scripts/|micro-ecc/test/|tiny-AES-c/" flags="VALUE_WORKSPACE_PATH|RESOLVED" kind="sourcePath" name="crypto"/>
+						<entry excluding=".settings/|CMSIS/|docs/|emlib/|GNU ARM v7.2.1 - Debug/|hw/|inc/|mbedtls/|sl_crypto/|src/.crypto.c.swp|src/.device.c.swp|src/app.h|src/main.c|.cproject|.project|EFM32.hwconf|Makefile|src/crypto.c" flags="VALUE_WORKSPACE_PATH|RESOLVED" kind="sourcePath" name="efm32"/>
+						<entry excluding=".ctap_errors.h.swp|.ctap.c.swp|.ctap.h.swp|.main.c.swp|.storage.h.swp|.wallet.c.swp|.wallet.h.swp|crypto.c|main.c|ctap_parse.c" flags="VALUE_WORKSPACE_PATH|RESOLVED" kind="sourcePath" name="fido2"/>
 					</sourceEntries>
 				</configuration>
 			</storageModule>
diff --git a/efm32boot/inc/app.h b/efm32boot/inc/app.h
index a01d6f5..8fe4a8b 100644
--- a/efm32boot/inc/app.h
+++ b/efm32boot/inc/app.h
@@ -16,7 +16,18 @@
 
 #define BRIDGE_TO_WALLET
 
+#define JUMP_LOC	0x8000
+
+#define PUSH_BUTTON		gpioPortF,6
+
+#define DISABLE_CTAPHID_PING
+#define DISABLE_CTAPHID_WINK
+#define DISABLE_CTAPHID_CBOR
+
 void printing_init();
 
+int bootloader_bridge(uint8_t klen, uint8_t * keyh);
+
+int is_authorized_to_boot();
 
 #endif /* SRC_APP_H_ */
diff --git a/efm32boot/src/boot.c b/efm32boot/src/boot.c
new file mode 100644
index 0000000..605d1d0
--- /dev/null
+++ b/efm32boot/src/boot.c
@@ -0,0 +1,98 @@
+/**************************************************************************//**
+ * @file boot.c
+ * @brief Functions for booting another application
+ * @author Silicon Labs
+ * @version 1.03
+ ******************************************************************************
+ * @section License
+ * <b>(C) Copyright 2014 Silicon Labs, http://www.silabs.com</b>
+ *******************************************************************************
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ *
+ * DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Silicon Labs has no
+ * obligation to support this Software. Silicon Labs is providing the
+ * Software "AS IS", with no express or implied warranties of any kind,
+ * including, but not limited to, any implied warranties of merchantability
+ * or fitness for any particular purpose or warranties against infringement
+ * of any proprietary rights of a third party.
+ *
+ * Silicon Labs will not be liable for any consequential, incidental, or
+ * special damages, or any other relief, or for any claim by any third party,
+ * arising from your use of this Software.
+ *
+ ******************************************************************************/
+
+#include "em_device.h"
+#include "em_gpio.h"
+#include "em_cmu.h"
+#include "app.h"
+
+
+/******************************************************************************
+ * This function sets up the Cortex-M3 with a new SP and PC.
+ *****************************************************************************/
+#if defined ( __CC_ARM   )
+__asm void BOOT_jump(uint32_t sp, uint32_t pc)
+{
+  /* Set new MSP, PSP based on SP (r0)*/
+  msr msp, r0
+  msr psp, r0
+
+  /* Jump to PC (r1)*/
+  bx r1
+}
+#else
+void BOOT_jump(uint32_t sp, uint32_t pc)
+{
+  (void) sp;
+  (void) pc;
+  /* Set new MSP, PSP based on SP (r0)*/
+  __asm("msr msp, r0");
+  __asm("msr psp, r0");
+
+  /* Jump to PC (r1)*/
+  __asm("mov pc, r1");
+}
+#endif
+
+
+/* Resets any peripherals that have been in use by
+ * the bootloader before booting the appliation */
+static void resetPeripherals(void)
+{
+
+}
+
+
+
+/******************************************************************************
+ * Boots the firmware. This function will activate the vector table
+ * of the firmware application and set the PC and SP from this table.
+ *****************************************************************************/
+void BOOT_boot(void)
+{
+  uint32_t pc, sp;
+
+  uint32_t *bootAddress = (uint32_t *)(JUMP_LOC);
+
+  resetPeripherals();
+
+  /* Set new vector table */
+  SCB->VTOR = (uint32_t)bootAddress;
+
+  /* Read new SP and PC from vector table */
+  sp = bootAddress[0];
+  pc = bootAddress[1];
+
+  /* Do a jump by loading the PC and SP into the CPU registers */
+  BOOT_jump(sp, pc);
+}
diff --git a/efm32boot/src/main.c b/efm32boot/src/main.c
index d826c73..4238eb4 100644
--- a/efm32boot/src/main.c
+++ b/efm32boot/src/main.c
@@ -1,28 +1,106 @@
 #include "em_device.h"
 #include "em_chip.h"
+
 #include "device.h"
 #include "app.h"
+#include "u2f.h"
+#include "log.h"
 #include "InitDevice.h"
 
 void bootloader_init(void);
 
+
 int main(void)
 {
-  /* Chip errata */
-	CHIP_Init();
+    int count = 0;
+    uint32_t t1 = 0;
+    uint32_t t2 = 0;
+    uint32_t accum = 0;
+    uint32_t dt = 0;
+    uint8_t hidmsg[64];
+    /* Chip errata */
+    CHIP_Init();
 
-	EMU_enter_DefaultMode_from_RESET();
-	CMU_enter_DefaultMode_from_RESET();
-//	ADC0_enter_DefaultMode_from_RESET();
-	USART0_enter_DefaultMode_from_RESET();
-	USART1_enter_DefaultMode_from_RESET();
-	LDMA_enter_DefaultMode_from_RESET();
-	CRYOTIMER_enter_DefaultMode_from_RESET();
-	PORTIO_enter_DefaultMode_from_RESET();
+    EMU_enter_DefaultMode_from_RESET();
+    CMU_enter_DefaultMode_from_RESET();
+    //	ADC0_enter_DefaultMode_from_RESET();
+    USART0_enter_DefaultMode_from_RESET();
+    USART1_enter_DefaultMode_from_RESET();
+    //	LDMA_enter_DefaultMode_from_RESET();
+    CRYOTIMER_enter_DefaultMode_from_RESET();
+    PORTIO_enter_DefaultMode_from_RESET();
 
-	bootloader_init();
+    bootloader_init();
+
+    set_logging_mask(
+            /*0*/
+           TAG_GEN|
+            /*TAG_MC |*/
+            /*TAG_GA |*/
+            /*TAG_WALLET |*/
+            TAG_STOR |
+            /*TAG_CP |*/
+//            TAG_CTAP|
+            /*TAG_HID|*/
+            /*TAG_U2F|*/
+            /*TAG_PARSE |*/
+//            TAG_TIME|
+            /*TAG_DUMP|*/
+            /*TAG_GREEN|*/
+            /*TAG_RED|*/
+            TAG_ERR
+            );
+
+    printf("Bootloader init\r\n");
+
+    if (GPIO_PinInGet(PUSH_BUTTON) == 0)
+    {
+        t1 = millis();
+        while(GPIO_PinInGet(PUSH_BUTTON) == 0 && (millis() - t1) < 2000)
+            ;
+        if (GPIO_PinInGet(PUSH_BUTTON) == 0) {
+bootmode:
+            printf("Reflash condition detected\n");
+            ctaphid_init();
+            /* Infinite loop */
+            int count = 0;
+            while (1) {
+                if (millis() - t1 > 1000)
+                {
+                    /*printf("heartbeat %ld\n", beat++);*/
+                    heartbeat();
+                    t1 = millis();
+                }
+
+                if (usbhid_recv(hidmsg) > 0)
+                {
+                    /*printf("%d>> ",count++); dump_hex1(TAG_DUMP, hidmsg,sizeof(hidmsg));*/
+                    //		            t2 = millis();
+                    ctaphid_handle_packet(hidmsg);
+                    //		            accum += millis() - t2;
+                    //		            printf("accum: %d\n", (uint32_t)accum);
+                    //		            printf("dt: %d\n", t2 - dt);
+                    //		            dt = t2;
+                    memset(hidmsg, 0, sizeof(hidmsg));
+                }
+                else
+                {
+                    /*main_loop_delay();*/
+                }
+                ctaphid_check_timeouts();
+
+            }
+        }
+    }
+
+    printf("Normal boot\n");
+
+    if (is_authorized_to_boot())
+    {
+        BOOT_boot();
+    } else {
+        printf("Warning: not authorized to boot\n");
+        goto bootmode;
+    }
 
-	/* Infinite loop */
-	while (1) {
-	}
 }
diff --git a/fido2/ctaphid.c b/fido2/ctaphid.c
index 81eea35..42419db 100644
--- a/fido2/ctaphid.c
+++ b/fido2/ctaphid.c
@@ -9,6 +9,7 @@
 #include "time.h"
 #include "util.h"
 #include "log.h"
+#include "app.h"
 
 typedef enum
 {
@@ -497,10 +498,12 @@ void ctaphid_handle_packet(uint8_t * pkt_raw)
         case BUFFERED:
             switch(buffer_cmd())
             {
+
                 case CTAPHID_INIT:
                     printf2(TAG_ERR,"CTAPHID_INIT, error this should already be handled\n");
                     exit(1);
                     break;
+#ifndef DISABLE_CTAPHID_PING
                 case CTAPHID_PING:
                     printf1(TAG_HID,"CTAPHID_PING\n");
 
@@ -514,7 +517,8 @@ void ctaphid_handle_packet(uint8_t * pkt_raw)
                     t2 = millis();
                     printf1(TAG_TIME,"PING writeback: %d ms\n",(uint32_t)(t2-t1));
                     break;
-
+#endif
+#ifndef DISABLE_CTAPHID_WINK
                 case CTAPHID_WINK:
                     printf1(TAG_HID,"CTAPHID_WINK\n");
 
@@ -526,7 +530,8 @@ void ctaphid_handle_packet(uint8_t * pkt_raw)
                     ctaphid_write(&wb,NULL,0);
 
                     break;
-
+#endif
+#ifndef DISABLE_CTAPHID_CBOR
                 case CTAPHID_CBOR:
                     printf1(TAG_HID,"CTAPHID_CBOR\n");
                     if (buffer_len() == 0)
@@ -552,7 +557,7 @@ void ctaphid_handle_packet(uint8_t * pkt_raw)
                     t2 = millis();
                     printf1(TAG_TIME,"CBOR writeback: %d ms\n",(uint32_t)(t2-t1));
                     break;
-
+#endif
                 case CTAPHID_MSG:
                     printf1(TAG_HID,"CTAPHID_MSG\n");
                     if (buffer_len() == 0)
diff --git a/fido2/u2f.c b/fido2/u2f.c
index a1a0071..34bb3e3 100644
--- a/fido2/u2f.c
+++ b/fido2/u2f.c
@@ -31,8 +31,10 @@ void u2f_request(struct u2f_request_apdu* req, CTAP_RESPONSE * resp)
         rcode = U2F_SW_CLASS_NOT_SUPPORTED;
         goto end;
     }
-#ifdef BRIDGE_TO_WALLET
+#if defined(BRIDGE_TO_WALLET)
     struct u2f_authenticate_request * auth = (struct u2f_authenticate_request *) req->payload;
+
+
     if (req->ins == U2F_AUTHENTICATE)
     {
         if (req->p1 == U2F_AUTHENTICATE_CHECK)
@@ -77,6 +79,7 @@ void u2f_request(struct u2f_request_apdu* req, CTAP_RESPONSE * resp)
     {
         rcode = U2F_SW_INS_NOT_SUPPORTED;
     }
+
 #else
     switch(req->ins)
     {
diff --git a/fido2/wallet.c b/fido2/wallet.c
index 2383aeb..329cc9b 100644
--- a/fido2/wallet.c
+++ b/fido2/wallet.c
@@ -200,12 +200,6 @@ int16_t bridge_u2f_to_wallet(uint8_t * _chal, uint8_t * _appid, uint8_t klen, ui
 
     memset(lens,0,sizeof(lens));
 
-
-    for (i = 0; i < sizeof(sig); i++)
-    {
-        sig[i] = i;
-    }
-
     wallet_request * req = (wallet_request *) msg_buf;
     uint8_t * payload = req->payload;
 
@@ -219,12 +213,15 @@ int16_t bridge_u2f_to_wallet(uint8_t * _chal, uint8_t * _appid, uint8_t klen, ui
     }
     else
     {
-        count = 0;
+        count = 10;
     }
+
     u2f_response_writeback(&up,1);
     u2f_response_writeback((uint8_t *)&count,4);
     u2f_response_writeback((uint8_t *)&ret,1);
 
+#ifndef IS_BOOTLOADER
+
     int offset = 0;
     for (i = 0; i < MIN(5,req->numArgs); i++)
     {
@@ -454,6 +451,9 @@ int16_t bridge_u2f_to_wallet(uint8_t * _chal, uint8_t * _appid, uint8_t klen, ui
             ret = CTAP1_ERR_INVALID_COMMAND;
             break;
     }
+#else
+    ret = bootloader_bridge(klen, keyh);
+#endif
 
 cleanup:
     if (ret != 0)
diff --git a/tools/http2udb.py b/tools/http2udb.py
index 41ea274..d4c3514 100644
--- a/tools/http2udb.py
+++ b/tools/http2udb.py
@@ -15,7 +15,7 @@ import socket,json,base64,ssl
 httpport = 8080
 udpport = 8111
 
-
+HEX_FILE = '../efm32/GNU ARM v7.2.1 - Debug/EFM32.hex'
 
 def ForceU2F(client,device):
     client.ctap = CTAP1(device)
@@ -25,13 +25,16 @@ def ForceU2F(client,device):
 
 
 if __name__ == '__main__':
-    dev = next(CtapHidDevice.list_devices(), None)
-    print(dev)
-    if not dev:
-        raise RuntimeError('No FIDO device found')
-    client = Fido2Client(dev, 'https://example.com')
-    ForceU2F(client, dev)
-    ctap = client.ctap
+    try:
+        dev = next(CtapHidDevice.list_devices(), None)
+        print(dev)
+        if not dev:
+            raise RuntimeError('No FIDO device found')
+        client = Fido2Client(dev, 'https://example.com')
+        ForceU2F(client, dev)
+        ctap = client.ctap
+    except Exception as e:
+        print(e)
 
 
 def to_websafe(data):
@@ -107,10 +110,15 @@ class UDPBridge(BaseHTTPRequestHandler):
     def do_GET(self):
         self.send_response(200)
         self.send_header('Content-type','text/json')
-        self.end_headers()
 
+        h = open(HEX_FILE,'r').read()
+        h = base64.b64encode(h.encode())
+        h = to_websafe(h.decode())
+        sig = [1,2,3,4]
         #msg = {'data': read()}
-        msg = {'data': 'rest'};
+        msg = {'firmware': h, 'signature':sig}
+
+        self.end_headers()
 
         self.wfile.write(json.dumps(msg).encode())
 
diff --git a/web/index.html b/web/index.html
index 9642222..b6283bf 100644
--- a/web/index.html
+++ b/web/index.html
@@ -3,10 +3,12 @@
 </head>
     <body>
         <h1>U2F Bridge Demo</h1>
+        <h3 id="progress"></h3>
     </body>
     <script src="js/u2f-api.js"></script>
     <script src="js/elliptic.js"></script>
     <script src="js/sha256.min.js"></script>
     <script src="js/aes.js"></script>
+    <script src="js/intel-hex.js"></script>
     <script src="js/wallet.js"></script>
 </html>
diff --git a/web/js/intel-hex.js b/web/js/intel-hex.js
new file mode 100644
index 0000000..347025b
--- /dev/null
+++ b/web/js/intel-hex.js
@@ -0,0 +1,977 @@
+(function (global, factory) {
+	typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
+	typeof define === 'function' && define.amd ? define(factory) :
+	(global.MemoryMap = factory());
+}(this, (function () { 'use strict';
+
+/**
+ * Parser/writer for the "Intel hex" format.
+ */
+
+/*
+ * A regexp that matches lines in a .hex file.
+ *
+ * One hexadecimal character is matched by "[0-9A-Fa-f]".
+ * Two hex characters are matched by "[0-9A-Fa-f]{2}"
+ * Eight or more hex characters are matched by "[0-9A-Fa-f]{8,}"
+ * A capture group of two hex characters is "([0-9A-Fa-f]{2})"
+ *
+ * Record mark         :
+ * 8 or more hex chars  ([0-9A-Fa-f]{8,})
+ * Checksum                              ([0-9A-Fa-f]{2})
+ * Optional newline                                      (?:\r\n|\r|\n|)
+ */
+var hexLineRegexp = /:([0-9A-Fa-f]{8,})([0-9A-Fa-f]{2})(?:\r\n|\r|\n|)/g;
+
+
+// Takes a Uint8Array as input,
+// Returns an integer in the 0-255 range.
+function checksum(bytes) {
+    return (-bytes.reduce(function (sum, v){ return sum + v; }, 0)) & 0xFF;
+}
+
+// Takes two Uint8Arrays as input,
+// Returns an integer in the 0-255 range.
+function checksumTwo(array1, array2) {
+    var partial1 = array1.reduce(function (sum, v){ return sum + v; }, 0);
+    var partial2 = array2.reduce(function (sum, v){ return sum + v; }, 0);
+    return -( partial1 + partial2 ) & 0xFF;
+}
+
+
+// Trivial utility. Converts a number to hex and pads with zeroes up to 2 characters.
+function hexpad(number) {
+    return number.toString(16).toUpperCase().padStart(2, '0');
+}
+
+
+// Polyfill as per https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isInteger
+Number.isInteger = Number.isInteger || function(value) {
+    return typeof value === 'number' &&
+    isFinite(value) &&
+    Math.floor(value) === value;
+};
+
+
+/**
+ * @class MemoryMap
+ *
+ * Represents the contents of a memory layout, with main focus into (possibly sparse) blocks of data.
+ *<br/>
+ * A {@linkcode MemoryMap} acts as a subclass of
+ * {@linkcode https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Map|Map}.
+ * In every entry of it, the key is the starting address of a data block (an integer number),
+ * and the value is the <tt>Uint8Array</tt> with the data for that block.
+ *<br/>
+ * The main rationale for this is that a .hex file can contain a single block of contiguous
+ * data starting at memory address 0 (and it's the common case for simple .hex files),
+ * but complex files with several non-contiguous data blocks are also possible, thus
+ * the need for a data structure on top of the <tt>Uint8Array</tt>s.
+ *<br/>
+ * In order to parse <tt>.hex</tt> files, use the {@linkcode MemoryMap.fromHex} <em>static</em> factory
+ * method. In order to write <tt>.hex</tt> files, create a new {@linkcode MemoryMap} and call
+ * its {@linkcode MemoryMap.asHexString} method.
+ *
+ * @extends Map
+ * @example
+ * import MemoryMap from 'nrf-intel-hex';
+ *
+ * let memMap1 = new MemoryMap();
+ * let memMap2 = new MemoryMap([[0, new Uint8Array(1,2,3,4)]]);
+ * let memMap3 = new MemoryMap({0: new Uint8Array(1,2,3,4)});
+ * let memMap4 = new MemoryMap({0xCF0: new Uint8Array(1,2,3,4)});
+ */
+var MemoryMap = function MemoryMap(blocks) {
+    var this$1 = this;
+
+    this._blocks = new Map();
+
+    if (blocks && typeof blocks[Symbol.iterator] === 'function') {
+        for (var tuple of blocks) {
+            if (!(tuple instanceof Array) || tuple.length !== 2) {
+                throw new Error('First parameter to MemoryMap constructor must be an iterable of [addr, bytes] or undefined');
+            }
+            this$1.set(tuple[0], tuple[1]);
+        }
+    } else if (typeof blocks === 'object') {
+        // Try iterating through the object's keys
+        var addrs = Object.keys(blocks);
+        for (var addr of addrs) {
+            this$1.set(parseInt(addr), blocks[addr]);
+        }
+
+    } else if (blocks !== undefined && blocks !== null) {
+        throw new Error('First parameter to MemoryMap constructor must be an iterable of [addr, bytes] or undefined');
+    }
+};
+
+var prototypeAccessors = { size: { configurable: true } };
+
+MemoryMap.prototype.set = function set (addr, value) {
+    if (!Number.isInteger(addr)) {
+        throw new Error('Address passed to MemoryMap is not an integer');
+    }
+    if (addr < 0) {
+        throw new Error('Address passed to MemoryMap is negative');
+    }
+    if (!(value instanceof Uint8Array)) {
+        throw new Error('Bytes passed to MemoryMap are not an Uint8Array');
+    }
+    return this._blocks.set(addr, value);
+};
+// Delegate the following to the 'this._blocks' Map:
+MemoryMap.prototype.get = function get (addr){ return this._blocks.get(addr);};
+MemoryMap.prototype.clear = function clear ()  { return this._blocks.clear();  };
+MemoryMap.prototype.delete = function delete$1 (addr) { return this._blocks.delete(addr); };
+MemoryMap.prototype.entries = function entries (){ return this._blocks.entries();};
+MemoryMap.prototype.forEach = function forEach (callback, that) { return this._blocks.forEach(callback, that); };
+MemoryMap.prototype.has = function has (addr){ return this._blocks.has(addr);};
+MemoryMap.prototype.keys = function keys ()   { return this._blocks.keys();   };
+MemoryMap.prototype.values = function values () { return this._blocks.values(); };
+prototypeAccessors.size.get = function ()   { return this._blocks.size;     };
+MemoryMap.prototype[Symbol.iterator] = function () { return this._blocks[Symbol.iterator](); };
+
+
+/**
+ * Parses a string containing data formatted in "Intel HEX" format, and
+ * returns an instance of {@linkcode MemoryMap}.
+ *<br/>
+ * The insertion order of keys in the {@linkcode MemoryMap} is guaranteed to be strictly
+ * ascending. In other words, when iterating through the {@linkcode MemoryMap}, the addresses
+ * will be ordered in ascending order.
+ *<br/>
+ * The parser has an opinionated behaviour, and will throw a descriptive error if it
+ * encounters some malformed input. Check the project's
+ * {@link https://github.com/NordicSemiconductor/nrf-intel-hex#Features|README file} for details.
+ *<br/>
+ * If <tt>maxBlockSize</tt> is given, any contiguous data block larger than that will
+ * be split in several blocks.
+ *
+ * @param {String} hexText The contents of a .hex file.
+ * @param {Number} [maxBlockSize=Infinity] Maximum size of the returned <tt>Uint8Array</tt>s.
+ *
+ * @return {MemoryMap}
+ *
+ * @example
+ * import MemoryMap from 'nrf-intel-hex';
+ *
+ * let intelHexString =
+ * ":100000000102030405060708090A0B0C0D0E0F1068\n" +
+ * ":00000001FF";
+ *
+ * let memMap = MemoryMap.fromHex(intelHexString);
+ *
+ * for (let [address, dataBlock] of memMap) {
+ * console.log('Data block at ', address, ', bytes: ', dataBlock);
+ * }
+ */
+MemoryMap.fromHex = function fromHex (hexText, maxBlockSize) {
+        if ( maxBlockSize === void 0 ) maxBlockSize = Infinity;
+
+    var blocks = new MemoryMap();
+
+    var lastCharacterParsed = 0;
+    var matchResult;
+    var recordCount = 0;
+
+    // Upper Linear Base Address, the 16 most significant bits (2 bytes) of
+    // the current 32-bit (4-byte) address
+    // In practice this is a offset that is summed to the "load offset" of the
+    // data records
+    var ulba = 0;
+
+    hexLineRegexp.lastIndex = 0; // Reset the regexp, if not it would skip content when called twice
+
+    while ((matchResult = hexLineRegexp.exec(hexText)) !== null) {
+        recordCount++;
+
+        // By default, a regexp loop ignores gaps between matches, but
+        // we want to be aware of them.
+        if (lastCharacterParsed !== matchResult.index) {
+            throw new Error(
+                'Malformed hex file: Could not parse between characters ' +
+                lastCharacterParsed +
+                ' and ' +
+                matchResult.index +
+                ' ("' +
+                hexText.substring(lastCharacterParsed, Math.min(matchResult.index, lastCharacterParsed + 16)).trim() +
+                '")');
+        }
+        lastCharacterParsed = hexLineRegexp.lastIndex;
+
+        // Give pretty names to the match's capture groups
+        var recordStr = matchResult[1];
+            var recordChecksum = matchResult[2];
+
+        // String to Uint8Array - https://stackoverflow.com/questions/43131242/how-to-convert-a-hexademical-string-of-data-to-an-arraybuffer-in-javascript
+        var recordBytes = new Uint8Array(recordStr.match(/[\da-f]{2}/gi).map(function (h){ return parseInt(h, 16); }));
+
+        var recordLength = recordBytes[0];
+        if (recordLength + 4 !== recordBytes.length) {
+            throw new Error('Mismatched record length at record ' + recordCount + ' (' + matchResult[0].trim() + '), expected ' + (recordLength) + ' data bytes but actual length is ' + (recordBytes.length - 4));
+        }
+
+        var cs = checksum(recordBytes);
+        if (parseInt(recordChecksum, 16) !== cs) {
+            throw new Error('Checksum failed at record ' + recordCount + ' (' + matchResult[0].trim() + '), should be ' + cs.toString(16) );
+        }
+
+        var offset = (recordBytes[1] << 8) + recordBytes[2];
+        var recordType = recordBytes[3];
+        var data = recordBytes.subarray(4);
+
+        if (recordType === 0) {
+            // Data record, contains data
+            // Create a new block, at (upper linear base address + offset)
+            if (blocks.has(ulba + offset)) {
+                throw new Error('Duplicated data at record ' + recordCount + ' (' + matchResult[0].trim() + ')');
+            }
+            if (offset + data.length > 0x10000) {
+                throw new Error(
+                    'Data at record ' +
+                    recordCount +
+                    ' (' +
+                    matchResult[0].trim() +
+                    ') wraps over 0xFFFF. This would trigger ambiguous behaviour. Please restructure your data so that for every record the data offset plus the data length do not exceed 0xFFFF.');
+            }
+
+            blocks.set( ulba + offset, data );
+
+        } else {
+
+            // All non-data records must have a data offset of zero
+            if (offset !== 0) {
+                throw new Error('Record ' + recordCount + ' (' + matchResult[0].trim() + ') must have 0000 as data offset.');
+            }
+
+            switch (recordType) {
+            case 1: // EOF
+                if (lastCharacterParsed !== hexText.length) {
+                    // This record should be at the very end of the string
+                    throw new Error('There is data after an EOF record at record ' + recordCount);
+                }
+
+                return blocks.join(maxBlockSize);
+
+            case 2: // Extended Segment Address Record
+                // Sets the 16 most significant bits of the 20-bit Segment Base
+                // Address for the subsequent data.
+                ulba = ((data[0] << 8) + data[1]) << 4;
+                break;
+
+            case 3: // Start Segment Address Record
+                // Do nothing. Record type 3 only applies to 16-bit Intel CPUs,
+                // where it should reset the program counter (CS+IP CPU registers)
+                break;
+
+            case 4: // Extended Linear Address Record
+                // Sets the 16 most significant (upper) bits of the 32-bit Linear Address
+                // for the subsequent data
+                ulba = ((data[0] << 8) + data[1]) << 16;
+                break;
+
+            case 5: // Start Linear Address Record
+                // Do nothing. Record type 5 only applies to 32-bit Intel CPUs,
+                // where it should reset the program counter (EIP CPU register)
+                // It might have meaning for other CPU architectures
+                // (see http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/ka9903.html )
+                // but will be ignored nonetheless.
+                break;
+            default:
+                throw new Error('Invalid record type 0x' + hexpad(recordType) + ' at record ' + recordCount + ' (should be between 0x00 and 0x05)');
+            }
+        }
+    }
+
+    if (recordCount) {
+        throw new Error('No EOF record at end of file');
+    } else {
+        throw new Error('Malformed .hex file, could not parse any registers');
+    }
+};
+
+
+/**
+ * Returns a <strong>new</strong> instance of {@linkcode MemoryMap}, containing
+ * the same data, but concatenating together those memory blocks that are adjacent.
+ *<br/>
+ * The insertion order of keys in the {@linkcode MemoryMap} is guaranteed to be strictly
+ * ascending. In other words, when iterating through the {@linkcode MemoryMap}, the addresses
+ * will be ordered in ascending order.
+ *<br/>
+ * If <tt>maxBlockSize</tt> is given, blocks will be concatenated together only
+ * until the joined block reaches this size in bytes. This means that the output
+ * {@linkcode MemoryMap} might have more entries than the input one.
+ *<br/>
+ * If there is any overlap between blocks, an error will be thrown.
+ *<br/>
+ * The returned {@linkcode MemoryMap} will use newly allocated memory.
+ *
+ * @param {Number} [maxBlockSize=Infinity] Maximum size of the <tt>Uint8Array</tt>s in the
+ * returned {@linkcode MemoryMap}.
+ *
+ * @return {MemoryMap}
+ */
+MemoryMap.prototype.join = function join (maxBlockSize) {
+        var this$1 = this;
+        if ( maxBlockSize === void 0 ) maxBlockSize = Infinity;
+
+
+    // First pass, create a Map of address→length of contiguous blocks
+    var sortedKeys = Array.from(this.keys()).sort(function (a,b){ return a-b; });
+    var blockSizes = new Map();
+    var lastBlockAddr = -1;
+    var lastBlockEndAddr = -1;
+
+    for (var i=0,l=sortedKeys.length; i<l; i++) {
+        var blockAddr = sortedKeys[i];
+        var blockLength = this$1.get(sortedKeys[i]).length;
+
+        if (lastBlockEndAddr === blockAddr && (lastBlockEndAddr - lastBlockAddr) < maxBlockSize) {
+            // Grow when the previous end address equals the current,
+            // and we don't go over the maximum block size.
+            blockSizes.set(lastBlockAddr, blockSizes.get(lastBlockAddr) + blockLength);
+            lastBlockEndAddr += blockLength;
+        } else if (lastBlockEndAddr <= blockAddr) {
+            // Else mark a new block.
+            blockSizes.set(blockAddr, blockLength);
+            lastBlockAddr = blockAddr;
+            lastBlockEndAddr = blockAddr + blockLength;
+        } else {
+            throw new Error('Overlapping data around address 0x' + blockAddr.toString(16));
+        }
+    }
+
+    // Second pass: allocate memory for the contiguous blocks and copy data around.
+    var mergedBlocks = new MemoryMap();
+    var mergingBlock;
+    var mergingBlockAddr = -1;
+    for (var i$1=0,l$1=sortedKeys.length; i$1<l$1; i$1++) {
+        var blockAddr$1 = sortedKeys[i$1];
+        if (blockSizes.has(blockAddr$1)) {
+            mergingBlock = new Uint8Array(blockSizes.get(blockAddr$1));
+            mergedBlocks.set(blockAddr$1, mergingBlock);
+            mergingBlockAddr = blockAddr$1;
+        }
+        mergingBlock.set(this$1.get(blockAddr$1), blockAddr$1 - mergingBlockAddr);
+    }
+
+    return mergedBlocks;
+};
+
+/**
+ * Given a {@link https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Map|<tt>Map</tt>}
+ * of {@linkcode MemoryMap}s, indexed by a alphanumeric ID,
+ * returns a <tt>Map</tt> of address to tuples (<tt>Arrays</tt>s of length 2) of the form
+ * <tt>(id, Uint8Array)</tt>s.
+ *<br/>
+ * The scenario for using this is having several {@linkcode MemoryMap}s, from several calls to
+ * {@link module:nrf-intel-hex~hexToArrays|hexToArrays}, each having a different identifier.
+ * This function locates where those memory block sets overlap, and returns a <tt>Map</tt>
+ * containing addresses as keys, and arrays as values. Each array will contain 1 or more
+ * <tt>(id, Uint8Array)</tt> tuples: the identifier of the memory block set that has
+ * data in that region, and the data itself. When memory block sets overlap, there will
+ * be more than one tuple.
+ *<br/>
+ * The <tt>Uint8Array</tt>s in the output are
+ * {@link https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/subarray|subarrays}
+ * of the input data; new memory is <strong>not</strong> allocated for them.
+ *<br/>
+ * The insertion order of keys in the output <tt>Map</tt> is guaranteed to be strictly
+ * ascending. In other words, when iterating through the <tt>Map</tt>, the addresses
+ * will be ordered in ascending order.
+ *<br/>
+ * When two blocks overlap, the corresponding array of tuples will have the tuples ordered
+ * in the insertion order of the input <tt>Map</tt> of block sets.
+ *<br/>
+ *
+ * @param {Map.MemoryMap} memoryMaps The input memory block sets
+ *
+ * @example
+ * import MemoryMap from 'nrf-intel-hex';
+ *
+ * let memMap1 = MemoryMap.fromHex( hexdata1 );
+ * let memMap2 = MemoryMap.fromHex( hexdata2 );
+ * let memMap3 = MemoryMap.fromHex( hexdata3 );
+ *
+ * let maps = new Map([
+ *  ['file A', blocks1],
+ *  ['file B', blocks2],
+ *  ['file C', blocks3]
+ * ]);
+ *
+ * let overlappings = MemoryMap.overlapMemoryMaps(maps);
+ *
+ * for (let [address, tuples] of overlappings) {
+ * // if 'tuples' has length > 1, there is an overlap starting at 'address'
+ *
+ * for (let [address, tuples] of overlappings) {
+ *     let [id, bytes] = tuple;
+ *     // 'id' in this example is either 'file A', 'file B' or 'file C'
+ * }
+ * }
+ * @return {Map.Array<mixed,Uint8Array>} The map of possibly overlapping memory blocks
+ */
+MemoryMap.overlapMemoryMaps = function overlapMemoryMaps (memoryMaps) {
+    // First pass: create a list of addresses where any block starts or ends.
+    var cuts = new Set();
+    for (var [, blocks] of memoryMaps) {
+        for (var [address, block] of blocks) {
+            cuts.add(address);
+            cuts.add(address + block.length);
+        }
+    }
+
+    var orderedCuts = Array.from(cuts.values()).sort(function (a,b){ return a-b; });
+    var overlaps = new Map();
+
+    // Second pass: iterate through the cuts, get slices of every intersecting blockset
+    var loop = function ( i, l ) {
+        var cut = orderedCuts[i];
+        var nextCut = orderedCuts[i+1];
+        var tuples = [];
+
+        for (var [setId, blocks$1] of memoryMaps) {
+            // Find the block with the highest address that is equal or lower to
+            // the current cut (if any)
+            var blockAddr = Array.from(blocks$1.keys()).reduce(function (acc, val){
+                if (val > cut) {
+                    return acc;
+                }
+                return Math.max( acc, val );
+            }, -1);
+
+            if (blockAddr !== -1) {
+                var block$1 = blocks$1.get(blockAddr);
+                var subBlockStart = cut - blockAddr;
+                var subBlockEnd = nextCut - blockAddr;
+
+                if (subBlockStart < block$1.length) {
+                    tuples.push([ setId, block$1.subarray(subBlockStart, subBlockEnd) ]);
+                }
+            }
+        }
+
+        if (tuples.length) {
+            overlaps.set(cut, tuples);
+        }
+    };
+
+        for (var i=0, l=orderedCuts.length-1; i<l; i++) loop( i, l );
+
+    return overlaps;
+};
+
+
+/**
+ * Given the output of the {@linkcode MemoryMap.overlapMemoryMaps|overlapMemoryMaps}
+ * (a <tt>Map</tt> of address to an <tt>Array</tt> of <tt>(id, Uint8Array)</tt> tuples),
+ * returns a {@linkcode MemoryMap}. This discards the IDs in the process.
+ *<br/>
+ * The output <tt>Map</tt> contains as many entries as the input one (using the same addresses
+ * as keys), but the value for each entry will be the <tt>Uint8Array</tt> of the <b>last</b>
+ * tuple for each address in the input data.
+ *<br/>
+ * The scenario is wanting to join together several parsed .hex files, not worrying about
+ * their overlaps.
+ *<br/>
+ *
+ * @param {Map.Array<mixed,Uint8Array>} overlaps The (possibly overlapping) input memory blocks
+ * @return {MemoryMap} The flattened memory blocks
+ */
+MemoryMap.flattenOverlaps = function flattenOverlaps (overlaps) {
+    return new MemoryMap(
+        Array.from(overlaps.entries()).map(function (ref) {
+                var address = ref[0];
+                var tuples = ref[1];
+
+            return [address, tuples[tuples.length - 1][1] ];
+        })
+    );
+};
+
+
+/**
+ * Returns a new instance of {@linkcode MemoryMap}, where:
+ *
+ * <ul>
+ *  <li>Each key (the start address of each <tt>Uint8Array</tt>) is a multiple of
+ *<tt>pageSize</tt></li>
+ *  <li>The size of each <tt>Uint8Array</tt> is exactly <tt>pageSize</tt></li>
+ *  <li>Bytes from the input map to bytes in the output</li>
+ *  <li>Bytes not in the input are replaced by a padding value</li>
+ * </ul>
+ *<br/>
+ * The scenario is wanting to prepare pages of bytes for a write operation, where the write
+ * operation affects a whole page/sector at once.
+ *<br/>
+ * The insertion order of keys in the output {@linkcode MemoryMap} is guaranteed
+ * to be strictly ascending. In other words, when iterating through the
+ * {@linkcode MemoryMap}, the addresses will be ordered in ascending order.
+ *<br/>
+ * The <tt>Uint8Array</tt>s in the output will be newly allocated.
+ *<br/>
+ *
+ * @param {Number} [pageSize=1024] The size of the output pages, in bytes
+ * @param {Number} [pad=0xFF] The byte value to use for padding
+ * @return {MemoryMap}
+ */
+MemoryMap.prototype.paginate = function paginate ( pageSize, pad) {
+        var this$1 = this;
+        if ( pageSize === void 0 ) pageSize=1024;
+        if ( pad === void 0 ) pad=0xFF;
+
+    if (pageSize <= 0) {
+        throw new Error('Page size must be greater than zero');
+    }
+    var outPages = new MemoryMap();
+    var page;
+
+    var sortedKeys = Array.from(this.keys()).sort(function (a,b){ return a-b; });
+
+    for (var i=0,l=sortedKeys.length; i<l; i++) {
+        var blockAddr = sortedKeys[i];
+        var block = this$1.get(blockAddr);
+        var blockLength = block.length;
+        var blockEnd = blockAddr + blockLength;
+
+        for (var pageAddr = blockAddr - (blockAddr % pageSize); pageAddr < blockEnd; pageAddr += pageSize) {
+            page = outPages.get(pageAddr);
+            if (!page) {
+                page = new Uint8Array(pageSize);
+                page.fill(pad);
+                outPages.set(pageAddr, page);
+            }
+
+            var offset = pageAddr - blockAddr;
+            var subBlock = (void 0);
+            if (offset <= 0) {
+                // First page which intersects the block
+                subBlock = block.subarray(0, Math.min(pageSize + offset, blockLength));
+                page.set(subBlock, -offset);
+            } else {
+                // Any other page which intersects the block
+                subBlock = block.subarray(offset, offset + Math.min(pageSize, blockLength - offset));
+                page.set(subBlock, 0);
+            }
+        }
+    }
+
+    return outPages;
+};
+
+
+/**
+ * Locates the <tt>Uint8Array</tt> which contains the given offset,
+ * and returns the four bytes held at that offset, as a 32-bit unsigned integer.
+ *
+ *<br/>
+ * Behaviour is similar to {@linkcode https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView/getUint32|DataView.prototype.getUint32},
+ * except that this operates over a {@linkcode MemoryMap} instead of
+ * over an <tt>ArrayBuffer</tt>, and that this may return <tt>undefined</tt> if
+ * the address is not <em>entirely</em> contained within one of the <tt>Uint8Array</tt>s.
+ *<br/>
+ *
+ * @param {Number} offset The memory offset to read the data
+ * @param {Boolean} [littleEndian=false] Whether to fetch the 4 bytes as a little- or big-endian integer
+ * @return {Number|undefined} An unsigned 32-bit integer number
+ */
+MemoryMap.prototype.getUint32 = function getUint32 (offset, littleEndian) {
+        var this$1 = this;
+
+    var keys = Array.from(this.keys());
+
+    for (var i=0,l=keys.length; i<l; i++) {
+        var blockAddr = keys[i];
+        var block = this$1.get(blockAddr);
+        var blockLength = block.length;
+        var blockEnd = blockAddr + blockLength;
+
+        if (blockAddr <= offset && (offset+4) <= blockEnd) {
+            return (new DataView(block.buffer, offset - blockAddr, 4)).getUint32(0, littleEndian);
+        }
+    }
+    return;
+};
+
+
+/**
+ * Returns a <tt>String</tt> of text representing a .hex file.
+ * <br/>
+ * The writer has an opinionated behaviour. Check the project's
+ * {@link https://github.com/NordicSemiconductor/nrf-intel-hex#Features|README file} for details.
+ *
+ * @param {Number} [lineSize=16] Maximum number of bytes to be encoded in each data record.
+ * Must have a value between 1 and 255, as per the specification.
+ *
+ * @return {String} String of text with the .hex representation of the input binary data
+ *
+ * @example
+ * import MemoryMap from 'nrf-intel-hex';
+ *
+ * let memMap = new MemoryMap();
+ * let bytes = new Uint8Array(....);
+ * memMap.set(0x0FF80000, bytes); // The block with 'bytes' will start at offset 0x0FF80000
+ *
+ * let string = memMap.asHexString();
+ */
+MemoryMap.prototype.asHexString = function asHexString (lineSize) {
+        var this$1 = this;
+        if ( lineSize === void 0 ) lineSize = 16;
+
+    var lowAddress  = 0;// 16 least significant bits of the current addr
+    var highAddress = -1 << 16; // 16 most significant bits of the current addr
+    var records = [];
+    if (lineSize <=0) {
+        throw new Error('Size of record must be greater than zero');
+    } else if (lineSize > 255) {
+        throw new Error('Size of record must be less than 256');
+    }
+
+    // Placeholders
+    var offsetRecord = new Uint8Array(6);
+    var recordHeader = new Uint8Array(4);
+
+    var sortedKeys = Array.from(this.keys()).sort(function (a,b){ return a-b; });
+    for (var i=0,l=sortedKeys.length; i<l; i++) {
+        var blockAddr = sortedKeys[i];
+        var block = this$1.get(blockAddr);
+
+        // Sanity checks
+        if (!(block instanceof Uint8Array)) {
+            throw new Error('Block at offset ' + blockAddr + ' is not an Uint8Array');
+        }
+        if (blockAddr < 0) {
+            throw new Error('Block at offset ' + blockAddr + ' has a negative thus invalid address');
+        }
+        var blockSize = block.length;
+        if (!blockSize) { continue; }   // Skip zero-length blocks
+
+
+        if (blockAddr > (highAddress + 0xFFFF)) {
+            // Insert a new 0x04 record to jump to a new 64KiB block
+
+            // Round up the least significant 16 bits - no bitmasks because they trigger
+            // base-2 negative numbers, whereas subtracting the modulo maintains precision
+            highAddress = blockAddr - blockAddr % 0x10000;
+            lowAddress = 0;
+
+            offsetRecord[0] = 2;// Length
+            offsetRecord[1] = 0;// Load offset, high byte
+            offsetRecord[2] = 0;// Load offset, low byte
+            offsetRecord[3] = 4;// Record type
+            offsetRecord[4] = highAddress >> 24;// new address offset, high byte
+            offsetRecord[5] = highAddress >> 16;// new address offset, low byte
+
+            records.push(
+                ':' +
+                Array.prototype.map.call(offsetRecord, hexpad).join('') +
+                hexpad(checksum(offsetRecord))
+            );
+        }
+
+        if (blockAddr < (highAddress + lowAddress)) {
+            throw new Error(
+                'Block starting at 0x' +
+                blockAddr.toString(16) +
+                ' overlaps with a previous block.');
+        }
+
+        lowAddress = blockAddr % 0x10000;
+        var blockOffset = 0;
+        var blockEnd = blockAddr + blockSize;
+        if (blockEnd > 0xFFFFFFFF) {
+            throw new Error('Data cannot be over 0xFFFFFFFF');
+        }
+
+        // Loop for every 64KiB memory segment that spans this block
+        while (highAddress + lowAddress < blockEnd) {
+
+            if (lowAddress > 0xFFFF) {
+                // Insert a new 0x04 record to jump to a new 64KiB block
+                highAddress += 1 << 16; // Increase by one
+                lowAddress = 0;
+
+                offsetRecord[0] = 2;// Length
+                offsetRecord[1] = 0;// Load offset, high byte
+                offsetRecord[2] = 0;// Load offset, low byte
+                offsetRecord[3] = 4;// Record type
+                offsetRecord[4] = highAddress >> 24;// new address offset, high byte
+                offsetRecord[5] = highAddress >> 16;// new address offset, low byte
+
+                records.push(
+                    ':' +
+                    Array.prototype.map.call(offsetRecord, hexpad).join('') +
+                    hexpad(checksum(offsetRecord))
+                );
+            }
+
+            var recordSize = -1;
+            // Loop for every record for that spans the current 64KiB memory segment
+            while (lowAddress < 0x10000 && recordSize) {
+                recordSize = Math.min(
+                    lineSize,                        // Normal case
+                    blockEnd - highAddress - lowAddress, // End of block
+                    0x10000 - lowAddress             // End of low addresses
+                );
+
+                if (recordSize) {
+
+                    recordHeader[0] = recordSize;   // Length
+                    recordHeader[1] = lowAddress >> 8;// Load offset, high byte
+                    recordHeader[2] = lowAddress;// Load offset, low byte
+                    recordHeader[3] = 0;// Record type
+
+                    var subBlock = block.subarray(blockOffset, blockOffset + recordSize);   // Data bytes for this record
+
+                    records.push(
+                        ':' +
+                        Array.prototype.map.call(recordHeader, hexpad).join('') +
+                        Array.prototype.map.call(subBlock, hexpad).join('') +
+                        hexpad(checksumTwo(recordHeader, subBlock))
+                    );
+
+                    blockOffset += recordSize;
+                    lowAddress += recordSize;
+                }
+            }
+        }
+    }
+
+    records.push(':00000001FF');// EOF record
+
+    return records.join('\n');
+};
+
+
+/**
+ * Performs a deep copy of the current {@linkcode MemoryMap}, returning a new one
+ * with exactly the same contents, but allocating new memory for each of its
+ * <tt>Uint8Array</tt>s.
+ *
+ * @return {MemoryMap}
+ */
+MemoryMap.prototype.clone = function clone () {
+        var this$1 = this;
+
+    var cloned = new MemoryMap();
+
+    for (var [addr, value] of this$1) {
+        cloned.set(addr, new Uint8Array(value));
+    }
+
+    return cloned;
+};
+
+
+/**
+ * Given one <tt>Uint8Array</tt>, looks through its contents and returns a new
+ * {@linkcode MemoryMap}, stripping away those regions where there are only
+ * padding bytes.
+ * <br/>
+ * The start of the input <tt>Uint8Array</tt> is assumed to be offset zero for the output.
+ * <br/>
+ * The use case here is dumping memory from a working device and try to see the
+ * "interesting" memory regions it has. This assumes that there is a constant,
+ * predefined padding byte value being used in the "non-interesting" regions.
+ * In other words: this will work as long as the dump comes from a flash memory
+ * which has been previously erased (thus <tt>0xFF</tt>s for padding), or from a
+ * previously blanked HDD (thus <tt>0x00</tt>s for padding).
+ * <br/>
+ * This method uses <tt>subarray</tt> on the input data, and thus does not allocate memory
+ * for the <tt>Uint8Array</tt>s.
+ *
+ * @param {Uint8Array} bytes The input data
+ * @param {Number} [padByte=0xFF] The value of the byte assumed to be used as padding
+ * @param {Number} [minPadLength=64] The minimum number of consecutive pad bytes to
+ * be considered actual padding
+ *
+ * @return {MemoryMap}
+ */
+MemoryMap.fromPaddedUint8Array = function fromPaddedUint8Array (bytes, padByte, minPadLength) {
+        if ( padByte === void 0 ) padByte=0xFF;
+        if ( minPadLength === void 0 ) minPadLength=64;
+
+
+    if (!(bytes instanceof Uint8Array)) {
+        throw new Error('Bytes passed to fromPaddedUint8Array are not an Uint8Array');
+    }
+
+    // The algorithm used is naïve and checks every byte.
+    // An obvious optimization would be to implement Boyer-Moore
+    // (see https://en.wikipedia.org/wiki/Boyer%E2%80%93Moore_string_search_algorithm )
+    // or otherwise start skipping up to minPadLength bytes when going through a non-pad
+    // byte.
+    // Anyway, we could expect a lot of cases where there is a majority of pad bytes,
+    // and the algorithm should check most of them anyway, so the perf gain is questionable.
+
+    var memMap = new MemoryMap();
+    var consecutivePads = 0;
+    var lastNonPad = -1;
+    var firstNonPad = 0;
+    var skippingBytes = false;
+    var l = bytes.length;
+
+    for (var addr = 0; addr < l; addr++) {
+        var byte = bytes[addr];
+
+        if (byte === padByte) {
+            consecutivePads++;
+            if (consecutivePads >= minPadLength) {
+                // Edge case: ignore writing a zero-length block when skipping
+                // bytes at the beginning of the input
+                if (lastNonPad !== -1) {
+                    /// Add the previous block to the result memMap
+                    memMap.set(firstNonPad, bytes.subarray(firstNonPad, lastNonPad+1));
+                }
+
+                skippingBytes = true;
+            }
+        } else {
+            if (skippingBytes) {
+                skippingBytes = false;
+                firstNonPad = addr;
+            }
+            lastNonPad = addr;
+            consecutivePads = 0;
+        }
+    }
+
+    // At EOF, add the last block if not skipping bytes already (and input not empty)
+    if (!skippingBytes && lastNonPad !== -1) {
+        memMap.set(firstNonPad, bytes.subarray(firstNonPad, l));
+    }
+
+    return memMap;
+};
+
+
+/**
+ * Returns a new instance of {@linkcode MemoryMap}, containing only data between
+ * the addresses <tt>address</tt> and <tt>address + length</tt>.
+ * Behaviour is similar to {@linkcode https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array/slice|Array.prototype.slice},
+ * in that the return value is a portion of the current {@linkcode MemoryMap}.
+ *
+ * <br/>
+ * The returned {@linkcode MemoryMap} might be empty.
+ *
+ * <br/>
+ * Internally, this uses <tt>subarray</tt>, so new memory is not allocated.
+ *
+ * @param {Number} address The start address of the slice
+ * @param {Number} length The length of memory map to slice out
+ * @return {MemoryMap}
+ */
+MemoryMap.prototype.slice = function slice (address, length){
+        var this$1 = this;
+        if ( length === void 0 ) length = Infinity;
+
+    if (length < 0) {
+        throw new Error('Length of the slice cannot be negative');
+    }
+
+    var sliced = new MemoryMap();
+
+    for (var [blockAddr, block] of this$1) {
+        var blockLength = block.length;
+
+        if ((blockAddr + blockLength) >= address && blockAddr < (address + length)) {
+            var sliceStart = Math.max(address, blockAddr);
+            var sliceEnd = Math.min(address + length, blockAddr + blockLength);
+            var sliceLength = sliceEnd - sliceStart;
+            var relativeSliceStart = sliceStart - blockAddr;
+
+            if (sliceLength > 0) {
+                sliced.set(sliceStart, block.subarray(relativeSliceStart, relativeSliceStart + sliceLength));
+            }
+        }
+    }
+    return sliced;
+};
+
+/**
+ * Returns a new instance of {@linkcode https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView/getUint32|Uint8Array}, containing only data between
+ * the addresses <tt>address</tt> and <tt>address + length</tt>. Any byte without a value
+ * in the input {@linkcode MemoryMap} will have a value of <tt>padByte</tt>.
+ *
+ * <br/>
+ * This method allocates new memory.
+ *
+ * @param {Number} address The start address of the slice
+ * @param {Number} length The length of memory map to slice out
+ * @param {Number} [padByte=0xFF] The value of the byte assumed to be used as padding
+ * @return {MemoryMap}
+ */
+MemoryMap.prototype.slicePad = function slicePad (address, length, padByte){
+        var this$1 = this;
+        if ( padByte === void 0 ) padByte=0xFF;
+
+    if (length < 0) {
+        throw new Error('Length of the slice cannot be negative');
+    }
+        
+    var out = (new Uint8Array(length)).fill(padByte);
+
+    for (var [blockAddr, block] of this$1) {
+        var blockLength = block.length;
+
+        if ((blockAddr + blockLength) >= address && blockAddr < (address + length)) {
+            var sliceStart = Math.max(address, blockAddr);
+            var sliceEnd = Math.min(address + length, blockAddr + blockLength);
+            var sliceLength = sliceEnd - sliceStart;
+            var relativeSliceStart = sliceStart - blockAddr;
+
+            if (sliceLength > 0) {
+                out.set(block.subarray(relativeSliceStart, relativeSliceStart + sliceLength), sliceStart - address);
+            }
+        }
+    }
+    return out;
+};
+
+/**
+ * Checks whether the current memory map contains the one given as a parameter.
+ *
+ * <br/>
+ * "Contains" means that all the offsets that have a byte value in the given
+ * memory map have a value in the current memory map, and that the byte values
+ * are the same.
+ *
+ * <br/>
+ * An empty memory map is always contained in any other memory map.
+ *
+ * <br/>
+ * Returns boolean <tt>true</tt> if the memory map is contained, <tt>false</tt>
+ * otherwise.
+ *
+ * @param {MemoryMap} memMap The memory map to check
+ * @return {Boolean}
+ */
+MemoryMap.prototype.contains = function contains (memMap) {
+        var this$1 = this;
+
+    for (var [blockAddr, block] of memMap) {
+
+        var blockLength = block.length;
+
+        var slice = this$1.slice(blockAddr, blockLength).join().get(blockAddr);
+
+        if ((!slice) || slice.length !== blockLength ) {
+            return false;
+        }
+
+        for (var i in block) {
+            if (block[i] !== slice[i]) {
+                return false;
+            }
+        }
+    }
+    return true;
+};
+
+Object.defineProperties( MemoryMap.prototype, prototypeAccessors );
+
+return MemoryMap;
+
+})));
+//# sourceMappingURL=intel-hex.browser.js.map
diff --git a/web/js/wallet.js b/web/js/wallet.js
index c41c487..babbcf5 100644
--- a/web/js/wallet.js
+++ b/web/js/wallet.js
@@ -76,6 +76,9 @@ function array2websafe(array) {
 function string2websafe(string) {
     return webSafe64(window.btoa(string));
 }
+function websafe2string(string) {
+    return window.atob(normal64(string));
+}
 function string2array(string) {
 
     var bytes = new Uint8Array( string.length );
@@ -233,6 +236,10 @@ var CMD = {
     reset: 0x13,
     version: 0x14,
     rng: 0x15,
+    boot_write: 0x40,
+    boot_done: 0x41,
+    boot_check: 0x42,
+    boot_erase: 0x43,
 };
 
 var PIN = {
@@ -305,6 +312,31 @@ function send_msg_http(data, func, timeout) {
     xhr.send(req);
 }
 
+function get_firmware_http_(func) {
+    var url = 'https://localhost:8080';
+
+    var xhr = createCORSRequest('GET', url);
+
+    if (!xhr) {
+        console.log('CORS not supported');
+        return;
+    }
+
+    // Response handlers.
+    xhr.onload = function() {
+        var text = xhr.responseText;
+        var resp = JSON.parse(text);
+        resp.firmware = websafe2string(resp.firmware);
+        if (func) func(resp);
+    };
+
+    xhr.onerror = function() {
+        console.log('Woops, there was an error making the request.');
+    };
+
+    xhr.send();
+}
+
 // For real
 function send_msg_u2f(data, func, timeout) {
     // Use key handle and signature response as comm channel
@@ -337,6 +369,8 @@ function send_msg_u2f(data, func, timeout) {
 
         var d2 = new Date();
         t2 = d2.getTime();
+        if (!res.signatureData)
+            func(res);
         sig = websafe2array(res.signatureData)
         data = parse_device_response(sig);
         func(data);
@@ -351,6 +385,37 @@ if (DEVELOPMENT) {
     send_msg = send_msg_u2f;
 }
 
+function formatBootRequest(cmd, addr, data) {
+    var array = new Uint8Array(255);
+
+    addr = addr || 0x8000;
+
+    data = data || new Uint8Array(1);
+
+    if (data.length > (255 - 9)) {
+        throw new Error("Max size exceeded");
+    }
+
+    array[0] = cmd & 0xff;
+    array[1] = (addr >> 0) & 0xff;
+    array[2] = (addr >> 8) & 0xff;
+    array[3] = (addr >> 16) & 0xff;
+
+    array[4] = 0x8C;    // Wallet tag.  To not interfere with U2F devices.
+    array[5] = 0x27;
+    array[6] = 0x90;
+    array[7] = 0xf6;
+
+    array[8] = data.length & 0xff;
+
+    var offset = 9;
+
+    var i;
+    for (i = 0; i < data.length; i++){
+        array[offset + i] = data[i];
+    }
+    return array;
+}
 
 // Format a request message
 // @cmd 0-255 value command
@@ -804,6 +869,40 @@ var get_rng_ = function(func){
     });
 };
 
+var is_bootloader_ = function(func){
+
+    var req = formatBootRequest(CMD.boot_check);
+
+    var self = this;
+
+    send_msg(req, function(resp){
+        if (func)func(resp);
+    });
+};
+
+var bootloader_finish_ = function(func){
+
+    var req = formatBootRequest(CMD.boot_done);
+
+    var self = this;
+
+    send_msg(req, function(resp){
+        if (func)func(resp);
+    });
+};
+
+var bootloader_write_ = function(addr,data,func){
+
+    var req = formatBootRequest(CMD.boot_write,addr,data);
+
+    var self = this;
+
+    send_msg(req, function(resp){
+        if (func)func(resp);
+    });
+};
+
+
 function wrap_promise(func)
 {
     var self = this;
@@ -836,6 +935,8 @@ function wrap_promise(func)
     }
 }
 
+var get_firmware_http = wrap_promise(get_firmware_http_);
+
 function WalletDevice() {
     var self = this;
     this.shared_secret = null;
@@ -885,6 +986,12 @@ function WalletDevice() {
 
     this.get_rng = get_rng_;
 
+    this.is_bootloader = is_bootloader_;
+
+    this.bootloader_write = bootloader_write_;
+
+    this.bootloader_finish = bootloader_finish_;
+
     this.init = wrap_promise.call(this, this.init);
     this.get_version = wrap_promise.call(this, this.get_version);
     this.get_shared_secret = wrap_promise.call(this, this.get_shared_secret );
@@ -897,6 +1004,9 @@ function WalletDevice() {
     this.register = wrap_promise.call(this, this.register );
     this.reset = wrap_promise.call(this,this.reset );
     this.get_rng = wrap_promise.call(this,this.get_rng);
+    this.is_bootloader = wrap_promise.call(this,this.is_bootloader);
+    this.bootloader_write = wrap_promise.call(this,this.bootloader_write);
+    this.bootloader_finish = wrap_promise.call(this,this.bootloader_finish);
 
 }
 
@@ -1205,19 +1315,55 @@ async function run_tests() {
         }
     }
 
-    while(1)
+    async function test_bootloader()
     {
-        await device_start_over();
-        await test_pin();
-        await test_crypto();
-        await test_rng();
+        var addr = 0x8000;
+
+        var p = await dev.is_bootloader();
+        TEST(p.status == 'CTAP1_SUCCESS', 'Device is in bootloader mode');
+
+        p = await get_firmware_http();
+
+        var blocks = MemoryMap.fromHex(p.firmware);
+        var addresses = blocks.keys();
+
+        var addr = addresses.next();
+        var chunk_size = 244;
+        while(!addr.done) {
+            var data = blocks.get(addr.value);
+            var i;
+            for (i = 0; i < data.length; i += chunk_size) {
+                var chunk = data.slice(i,i+chunk_size);
+                p = await dev.bootloader_write(addr.value + i, chunk);
+                TEST(p.status == 'CTAP1_SUCCESS', 'Device wrote data');
+                var progress = (((i/data.length) * 100 * 100) | 0)/100;
+                document.getElementById('progress').textContent = ''+progress+' %';
+            }
+
+            addr = addresses.next();
+        }
+
+        p = await dev.bootloader_finish();
+        console.log(p);
+
     }
+
+    //while(1)
+    //{
+        //await device_start_over();
+        //await test_pin();
+        //await test_crypto();
+        //await test_rng();
+    //}
     //await benchmark();
     //await test_persistence();
 
-}
+    await test_bootloader();
 
 
+}
+var test;
+
 EC = elliptic.ec
 
 run_tests()