diff --git a/make_helpers/defaults.mk b/make_helpers/defaults.mk
index 2eb922f..eb1bb0a 100644
--- a/make_helpers/defaults.mk
+++ b/make_helpers/defaults.mk
@@ -31,6 +31,10 @@
 # The platform Makefile is free to override this value.
 COLD_BOOT_SINGLE_CPU		:= 0
 
+# Flag to compile in coreboot support code. Exclude by default. The coreboot
+# Makefile system will set this when compiling TF as part of a coreboot image.
+COREBOOT			:= 0
+
 # For Chain of Trust
 CREATE_KEYS			:= 1