diff --git a/configs/espresso7420_defconfig b/configs/espresso7420_defconfig
index 22267bb..39837e9 100644
--- a/configs/espresso7420_defconfig
+++ b/configs/espresso7420_defconfig
@@ -3,6 +3,7 @@
 CONFIG_ARCH_EXYNOS7=y
 CONFIG_SYS_MALLOC_F_LEN=0x2000
 CONFIG_IDENT_STRING=" for ESPRESSO7420"
+# CONFIG_MMC is not set
 CONFIG_DEFAULT_DEVICE_TREE="exynos7420-espresso7420"
 CONFIG_SILENT_CONSOLE=y
 CONFIG_CONSOLE_MUX=y