diff --git a/src/mainboard/Kconfig b/src/mainboard/Kconfig
index 24c1fe3777..bdaa9e75c9 100644
--- a/src/mainboard/Kconfig
+++ b/src/mainboard/Kconfig
@@ -1,3 +1,5 @@
+comment "Important: Run 'make distclean' before switching boards"
+
 choice
 	prompt "Mainboard vendor"
 	default VENDOR_EMULATION