diff --git a/BaseTools/ReadMe.txt b/BaseTools/ReadMe.txt
index e50ac82c99..9ee693474b 100644
--- a/BaseTools/ReadMe.txt
+++ b/BaseTools/ReadMe.txt
@@ -28,7 +28,7 @@ Notes:
 	 cannot generate AutoGen.* files. Only "build" command can.
 3) build.exe in %WORKSPACE%\BaseTools\Bin\Win32 is generated from following revision of
    Python source code:
-        r601 <buildtools_project>\BaseTools\Source\Python\Autogen
+        r620 <buildtools_project>\BaseTools\Source\Python\Autogen
         r601 <buildtools_project>\BaseTools\Source\Python\Python\build
         r569 <buildtools_project>\BaseTools\Source\Python\Python\Common
         r564 <buildtools_project>\BaseTools\Source\Python\Python\CommonDataClass