diff --git a/configs/firefly_rk3288_demo_defconfig b/configs/firefly_rk3288_demo_defconfig
index 7dadc6bc9a..c2de701934 100644
--- a/configs/firefly_rk3288_demo_defconfig
+++ b/configs/firefly_rk3288_demo_defconfig
@@ -26,6 +26,7 @@ BR2_PACKAGE_QT5BASE_EGLFS=y
 BR2_PACKAGE_MALI_T76X=y
 BR2_TARGET_ROOTFS_EXT2=y
 BR2_TARGET_ROOTFS_EXT2_4=y
+BR2_TARGET_ROOTFS_EXT2_BLOCKS=250000
 # BR2_TARGET_ROOTFS_TAR is not set
 BR2_TARGET_UBOOT=y
 BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG=y