diff --git a/Makefile.inc b/Makefile.inc
index 7258043..9365a4a 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -823,7 +823,7 @@
 #
 # This is the default implementation. When using a boot strategy employing
 # multiple CBFSes in fmap regions, override it.
-regions-for-file ?= COREBOOT
+regions-for-file ?= $(if $(value regions-for-file-$(1)), $(regions-for-file-$(1)), COREBOOT)
 
 ifeq ($(CONFIG_CBFS_AUTOGEN_ATTRIBUTES),y)
 	cbfs-autogen-attributes=-g