diff --git a/scripts/combo-layer-hook-default.sh b/scripts/combo-layer-hook-default.sh
index f03c4fa80f..e535d5f4cc 100755
--- a/scripts/combo-layer-hook-default.sh
+++ b/scripts/combo-layer-hook-default.sh
@@ -9,5 +9,5 @@ patchfile=$1
 rev=$2
 reponame=$3
 
-sed -i -e "s#Subject: \[PATCH\] \(.*\)#Subject: \[PATCH\] $reponame: \1#" $patchfile
-sed -i -e "0,/Signed-off-by:/s#\(Signed-off-by:.*\)#\($reponame rev: $rev\)\n\n\1#" $patchfile
+sed -i -e "s#^Subject: \[PATCH\] \(.*\)#Subject: \[PATCH\] $reponame: \1#" $patchfile
+sed -i -e "0,/^Signed-off-by:/s#\(Signed-off-by:.*\)#\($reponame rev: $rev\)\n\n\1#" $patchfile