Build firmware .hex file too, for production

firmware/.gitignore

@@ -3,6 +3,7 @@
 *.a
 *.d
 *.dfu
+*.hex
 
 # IDA Pro
 *.id0

firmware/Makefile

@@ -52,7 +52,7 @@ LIBS = -lm
 
 OBJS := $(C_FILES:.c=.o) $(CPP_FILES:.cpp=.o)
 
-all: $(TARGET).dfu
+all: $(TARGET).dfu $(TARGET).hex
 
 $(TARGET).elf: $(OBJS) $(LDSCRIPT)
 	$(CC) $(LDFLAGS) -o $@ $(OBJS) $(LIBS)
@@ -62,6 +62,9 @@ $(TARGET).elf: $(OBJS) $(LDSCRIPT)
 	$(OBJCOPY) -O binary $< $@
 	$(DFU_SUFFIX) -a $@
 
+%.hex: %.elf
+	$(OBJCOPY) -O ihex $< $@
+
 install: $(TARGET).dfu
 	$(DFU_UTIL) -d 1d50 -D $<