diff --git a/Makefile.mk b/Makefile.mk
index e2b49b36fe..14f9b835d7 100644
--- a/Makefile.mk
+++ b/Makefile.mk
@@ -1085,6 +1085,8 @@ prebuild-files = $(foreach region,$(all-regions), \
 # If no FMD file (Flashmap) is supplied by mainboard, fall back to a default
 ifeq ($(CONFIG_FMDFILE),)
 
+FMAP_FLASH_SIZE := $(CONFIG_ROM_SIZE)
+
 ifeq ($(CONFIG_ARCH_X86),y)
 
 DEFAULT_FLASHMAP:=$(top)/util/cbfstool/default-x86.fmd
@@ -1098,8 +1100,6 @@ $(DEFAULT_FLASHMAP): $(call strip_quotes,$(CONFIG_IFD_BIN_PATH)) $(IFDTOOL)
 endif # ifeq($(CONFIG_HAVE_IFD_BIN),y)
 endif # ifneq($(CONFIG_IFD_CHIPSET),)
 
-# entire flash
-FMAP_FLASH_SIZE := $(CONFIG_ROM_SIZE)
 # entire "BIOS" region (everything directly of concern to the host system)
 FMAP_BIOS_BASE := $(call int-align, $(call int-subtract, $(CONFIG_ROM_SIZE) $(CONFIG_CBFS_SIZE)), 0x10000)
 FMAP_BIOS_SIZE := $(call int-align-down, $(shell echo $(CONFIG_CBFS_SIZE) | tr A-F a-f), 0x10000)
@@ -1186,7 +1186,6 @@ else # ifeq ($(CONFIG_ARCH_X86),y)
 
 DEFAULT_FLASHMAP:=$(top)/util/cbfstool/default.fmd
 # entire flash
-FMAP_FLASH_SIZE := $(CONFIG_ROM_SIZE)
 # entire "BIOS" region (everything directly of concern to the host system)
 FMAP_BIOS_BASE := 0
 FMAP_BIOS_SIZE := $(CONFIG_CBFS_SIZE)