diff --git a/src/include/fmap.h b/src/include/fmap.h
index 900bfff542..1fadaef3c5 100644
--- a/src/include/fmap.h
+++ b/src/include/fmap.h
@@ -13,6 +13,14 @@
 	#error "FMAP must always start flash address 0"
 #endif
 
+/* This is usually the case. And it can to lead to confusion if one them is updated without the
+ * other. There is however no code that has a hard dependency on this check. So if there comes
+ * a platform at some point, which has a Flashmap which doesn't cover the whole flash, we can
+ * remove the check again. */
+#if FMAP_SECTION_FLASH_SIZE != CONFIG_ROM_SIZE
+	#error "ROM_SIZE must always be equal to FMAP flash size"
+#endif
+
 /* Return the name of the boot region. Falls back to COREBOOT, if not overridden
  * by any multi-slot mechanism (e.g Intel Top Swap, vboot). */
 const char *cbfs_fmap_region_hint(void);
diff --git a/tests/Makefile.common b/tests/Makefile.common
index cfb6fe945e..085e4cffc4 100644
--- a/tests/Makefile.common
+++ b/tests/Makefile.common
@@ -18,7 +18,7 @@ CMAKE := cmake
 OBJCOPY ?= objcopy
 OBJDUMP ?= objdump
 
-TEST_DEFAULT_CONFIG ?= $(top)/configs/config.emulation_qemu_x86_i440fx
+TEST_DEFAULT_CONFIG ?= $(top)/configs/config.google_octopus_spi_flash_console
 TEST_DOTCONFIG := $(testobj)/.config
 TEST_KCONFIG_AUTOHEADER := $(testobj)/config.src.h
 TEST_KCONFIG_AUTOCONFIG := $(testobj)/auto.conf
diff --git a/tests/include/tests/lib/fmap_config.h b/tests/include/tests/lib/fmap_config.h
index 5b3540020b..690ee19fca 100644
--- a/tests/include/tests/lib/fmap_config.h
+++ b/tests/include/tests/lib/fmap_config.h
@@ -8,5 +8,6 @@
  * Keeps the build tests from failing since fmap.h needs fmap_config.h
  */
 #define FMAP_SECTION_FLASH_START 0
+#define FMAP_SECTION_FLASH_SIZE 0x1000000
 
 #endif