diff --git a/openwrt/target/Config.in b/openwrt/target/Config.in
index d93df6b1cf..dc9224ff9a 100644
--- a/openwrt/target/Config.in
+++ b/openwrt/target/Config.in
@@ -1,3 +1,5 @@
+comment "after changing root fs, use make linux-dirclean"
+
 choice
 	prompt "Target Root Filesystem"
 	source "target/jffs2/Config.in"