diff --git a/configs/x600_defconfig b/configs/x600_defconfig
index 65b7d95..4b47fc6 100644
--- a/configs/x600_defconfig
+++ b/configs/x600_defconfig
@@ -4,6 +4,7 @@
 CONFIG_SPL_LIBGENERIC_SUPPORT=y
 CONFIG_SPL_SERIAL_SUPPORT=y
 CONFIG_IDENT_STRING="-SPEAr"
+# CONFIG_MMC is not set
 CONFIG_BOOTDELAY=3
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
 # CONFIG_DISPLAY_BOARDINFO is not set