diff --git a/Makefile b/Makefile
index 8fe897b..6f8f22a 100644
--- a/Makefile
+++ b/Makefile
@@ -58,8 +58,8 @@ $(info run "git submodule init" and "git submodule update" before runnig make)
 $(error libopencm3 repository is not initialized)
 endif
 
-# device flag
-DEFS += -DSTM32F1
+# device flags
+DEFS += -DSTM32F1 -D$(BOARD)
 
 # C flags
 CFLAGS += -Os -g