Index: ltsp-5.4.2/server/ltsp-update-image
===================================================================
--- ltsp-5.4.2.orig/server/ltsp-update-image	2012-06-27 14:26:21.000000000 -0700
+++ ltsp-5.4.2/server/ltsp-update-image	2012-10-05 15:43:49.633052403 -0700
@@ -187,7 +187,7 @@
 
         test -f /etc/ltsp/ltsp-update-image.excludes && EXCLUDE_FILE="/etc/ltsp/ltsp-update-image.excludes"
         test -x /usr/bin/nice && nice=nice || unset nice
-        test -x /usr/bin/ionice && /usr/bin/ionice -c3 true 2>/dev/null && ionice=ionice || unset ionice
+        test -x /usr/bin/ionice && /usr/bin/ionice -c3 true 2>/dev/null && ionice="ionice -c3" || unset ionice
         if ! $nice $ionice mksquashfs "$cu_chroot" "$imgdir/$name.img.tmp" \
             -no-recovery -noappend -wildcards ${EXCLUDE_FILE:+-ef "$EXCLUDE_FILE"} \
             ${EXCLUDE:+-e "$EXCLUDE"} ${NO_COMPRESS:+-noF -noD -noI -no-exports}
