+# bootloader definitions may be used in the startup .s file
+ifneq ("$(wildcard $(TARGET_DIR)/bootloader_defs.h)","")
+ UADEFS += -include $(TARGET_DIR)/bootloader_defs.h
+ UDEFS += -include $(TARGET_DIR)/bootloader_defs.h
+else ifneq ("$(wildcard $(TARGET_DIR)/boards/$(BOARD)/bootloader_defs.h)","")
+ UADEFS += -include $(TARGET_DIR)/boards/$(BOARD)/bootloader_defs.h
+ UDEFS += -include $(TARGET_DIR)/boards/$(BOARD)/bootloader_defs.h
+endif