diff --git a/Makefile.mk b/Makefile.mk
index f7b98c7..73fb40b 100644
--- a/Makefile.mk
+++ b/Makefile.mk
@@ -481,6 +481,7 @@
 CPPFLAGS_common += -include $(src)/commonlib/bsd/include/commonlib/bsd/compiler.h
 CPPFLAGS_common += -I3rdparty
 CPPFLAGS_common += -D__BUILD_DIR__=\"$(obj)\"
+CPPFLAGS_common += -D__COREBOOT__
 
 ifeq ($(BUILD_TIMELESS),1)
 CPPFLAGS_common += -D__TIMELESS__