--- util/gensdsk.orig	2015-06-05 17:32:57 UTC
+++ util/gensdsk
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 #
 # Generate a syslinux floppy that loads a iPXE image
 #
@@ -44,8 +44,7 @@ do
 	# shorten name for 8.3 filesystem
 	b=$(basename $f)
 	g=${b%.lkrn}
-	g=${g//[^a-z0-9]}
-	g=${g:0:8}.krn
+	g=$(echo $g | sed -e 's/[^a-z0-9]//g' | cut -c1-8).krn
 	case "$first" in
 	"")
 		echo DEFAULT $g