diff --git a/Makefile b/Makefile
index 04b4619..52815b8 100644
--- a/Makefile
+++ b/Makefile
@@ -15,7 +15,8 @@ EFM32_DEBUGGER= -s 440083537 --device EFM32JG1B200F128GM32
 src = $(wildcard pc/*.c) $(wildcard fido2/*.c) $(wildcard crypto/sha256/*.c) crypto/tiny-AES-c/aes.c
 obj = $(src:.c=.o) uECC.o
 
-LDFLAGS = -Wl,--gc-sections ./tinycbor/lib/libtinycbor.a
+LIBCBOR = tinycbor/lib/libtinycbor.a
+LDFLAGS = -Wl,--gc-sections $(LIBCBOR)
 CFLAGS = -O2 -fdata-sections -ffunction-sections 
 
 INCLUDES = -I./tinycbor/src -I./crypto/sha256 -I./crypto/micro-ecc/ -Icrypto/tiny-AES-c/ -I./fido2/ -I./pc -I./fido2/extensions
@@ -24,11 +25,20 @@ CFLAGS += $(INCLUDES)
 
 name = main
 
+.PHONY: all
 all: main
 
-cbor:
+
+tinycbor/Makefile crypto/tiny-AES-c/aes.h:
+	git submodule update --init
+
+.PHONY: cbor
+cbor: $(LIBCBOR)
+
+$(LIBCBOR): tinycbor/Makefile
 	cd tinycbor/ && $(MAKE) clean && $(MAKE) -j8
 
+.PHONY: test
 test: testgcm
 
 efm8prog:
@@ -51,10 +61,19 @@ efm32bootprog:
 	cd './targets/efm32boot/GNU ARM v7.2.1 - Debug' && $(MAKE) all
 	commander flash './efm32boot/GNU ARM v7.2.1 - Debug/efm32boot.hex' $(EFM32_DEBUGGER) --masserase
 
-$(name):  $(obj)
+
+crypto/tiny-AES-c/aes.o:
+	if ! grep "^#define AES256" crypto/tiny-AES-c/aes.h ; then \
+		echo "Fixing crypto/tiny-AES-c/aes.h" ;\
+		sed -i 's/^#define AES1\/\/#define AES1; s/^\/*#define AES256/#define AES256/' crypto/tiny-AES-c/aes.h ;\
+	fi
+	$(CC) $(CFLAGS) -c -o crypto/tiny-AES-c/aes.o crypto/tiny-AES-c/aes.c
+
+
+$(name): $(obj) $(LIBCBOR)
 	$(CC) $(LDFLAGS) -o $@ $(obj) $(LDFLAGS)
 
-testgcm: $(obj)
+testgcm: $(obj) $(LIBCBOR)
 	$(CC) -c main.c $(CFLAGS) -DTEST -o main.o
 	$(CC) -c crypto/aes_gcm.c $(CFLAGS) -DTEST -o crypto/aes_gcm.o
 	$(CC) $(LDFLAGS) -o $@ $^ $(LDFLAGS)
@@ -64,3 +83,9 @@ uECC.o: ./crypto/micro-ecc/uECC.c
 
 clean:
 	rm -f *.o main.exe main $(obj)
+	for f in crypto/tiny-AES-c/Makefile tinycbor/Makefile ; do \
+	    if [ -f "$$f" ]; then \
+	    	(cd `dirname $$f` ; git co -- .) ;\
+	    fi ;\
+	done
+