diff --git a/DuetPkg/FSVariable/FSVariable.inf b/DuetPkg/FSVariable/FSVariable.inf
index 83268381d3..ad9037a858 100644
--- a/DuetPkg/FSVariable/FSVariable.inf
+++ b/DuetPkg/FSVariable/FSVariable.inf
@@ -1,5 +1,11 @@
 ## @file
 #
+# Caution: This file is used for Duet platform only, do not use them in real platform.
+# All variable code, variable metadata, and variable data used by Duet platform are on 
+# disk. They can be changed by user. BIOS is not able to protoect those.
+# Duet trusts all meta data from disk. If variable code, variable metadata and variable
+# data is modified in inproper way, the behavior is undefined.
+#
 # Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
 # This program and the accompanying materials                          
 # are licensed and made available under the terms and conditions of the BSD License