diff --git a/kiwi/boot/functions.sh b/kiwi/boot/functions.sh
index 1856d8b8..3490551c 100644
--- a/kiwi/boot/functions.sh
+++ b/kiwi/boot/functions.sh
@@ -4498,7 +4498,8 @@ function partedGetPartitionID {
         local name=$(parted -m -s $1 print | grep ^$2: | cut -f6 -d:)
         if lookup sgdisk &>/dev/null;then
             # map to short gdisk code
-            echo $(sgdisk -p $1 | grep -E "^   $2") | cut -f6 -d ' ' | cut -c-2
+            echo $(sgdisk -p $1 | grep -E "^   $2") |\
+                cut -f6 -d ' ' | cut -c-2 | tr [:upper:] [:lower:]
         elif [ "$name" = "lxroot" ];then
             # map lxroot to MBR type 83 (linux)
             echo 83