diff --git a/Makefile.include b/Makefile.include
index 43713b27b4a657aa25a557fd2bb66347fdbc23b6..e5fadea98443d69fb7bbee05971f8115d5c46156 100644
--- a/Makefile.include
+++ b/Makefile.include
@@ -2,6 +2,9 @@ ifeq ($(strip $(RIOTCPU)),)
 	export RIOTCPU =$(RIOTBASE)/cpu
 endif
 	
+ifeq ($(strip $(MCU)),)
+	MCU = $(CPU)
+endif
 
 # if you want to publish the board into the sources as an uppercase #define
 BB = $(shell echo $(BOARD)|tr 'a-z' 'A-Z')