diff --git a/utils/tweak.in b/utils/tweak.in
--- a/utils/tweak.in
+++ b/utils/tweak.in
@@ -3,8 +3,8 @@

 myname=${0##*/}

-# If no prefix forced, use the default CONFIG_
-CONFIG_="${CONFIG_-CONFIG_}"
+# If no prefix forced, use the default @CONFIG_@
+CONFIG_="${CONFIG_-@CONFIG_@}"

 usage() {
 	cat >&2 <<EOL
@@ -41,7 +41,7 @@
 By default, $myname will upper-case the given symbol. Use --keep-case to keep
 the case of all following symbols unchanged.

-$myname uses 'CONFIG_' as the default symbol prefix. Set the environment
+$myname uses '@CONFIG_@' as the default symbol prefix. Set the environment
 variable CONFIG_ to the prefix to use. Eg.: CONFIG_="FOO_" $myname ...
 EOL
 	exit 1