if [ -n "$fw_mtd" ] && [ ${fw_blocks:-0} -gt 0 ]; then
local append=""
- [ -f "$UPGRADE_BACKUP" ] && append="-j $UPGRADE_BACKUPs"
+ [ -f "$UPGRADE_BACKUP" ] && append="-j $UPGRADE_BACKUP"
sync
dd if="$fw_file" bs=64k skip=1 count=$fw_blocks 2>/dev/null | \