# Netgear WNCE2001 has does a checksum check on boot and goes into recovery
# tftp mode when the check fails.  Initializing the JFFS2 partition triggers
# this, so we make sure to zero checksum and size to be checksummed before
# that happens, so this needs to run very early during boot.

do_checksumming_disable() {
	. /lib/functions.sh

	local board=$(board_name)

	case "$board" in
	asus,rt-n56u)
		echo "Board is ASUS RT-N56U, replacing uImage header..."
		local firmware_mtd=$(find_mtd_part firmware)
		local rootfs_mtd=$(find_mtd_part rootfs)
		local rootfs_data_mtd=$(find_mtd_part rootfs_data)
		local rootfs_len=$(grep \"rootfs\" /proc/mtd | awk -F' ' '{print "0x"$2}')
		local rootfs_data_len=$(grep \"rootfs_data\" /proc/mtd | awk -F' ' '{print "0x"$2}')
		local offset=$(echo "$rootfs_len $rootfs_data_len 0x40" | awk -F' ' '{printf "%i",$1-$2-$3}')
		local signature=$(dd if=$rootfs_mtd skip=$offset bs=1 count=4 2>/dev/null | hexdump -v -n 4 -e '1/1 "%02x"')
		if [ "$signature" = "27051956" ]; then
			dd conv=notrunc if=$rootfs_mtd skip=$offset of=$firmware_mtd bs=1 count=64 2>/dev/null
		fi
	;;
	esac

	return 0
}

boot_hook_add preinit_main do_checksumming_disable