1#!/bin/sh
2
3# Netgear WNCE2001 has does a checksum check on boot and goes into recovery
4# tftp mode when the check fails.  Initializing the JFFS2 partition triggers
5# this, so we make sure to zero checksum and size to be checksummed before
6# that happens, so this needs to run very early during boot.
7
8do_checksumming_disable() {
9	. /lib/ramips.sh
10
11	local board=$(ramips_board_name)
12
13	case "$board" in
14	wnce2001)
15		echo "Board is WNCE2001, updating checksum partition..."
16		local zeroes=/dev/zero
17		local tmpfile=/tmp/wnce2001_checksum
18		local partname=checksum
19		local mtd=$(find_mtd_part $partname)
20		dd if=$mtd of=$tmpfile bs=80 count=1 2>/dev/null
21		signature=$(dd if=$tmpfile bs=1 skip=24 count=20 2>/dev/null)
22		checksum=$(dd if=$tmpfile bs=1 count=4 2>/dev/null | hexdump -v -n 4 -e '1/1 "%02x"')
23		if [ "$signature" != "RT3052-AP-WNCE2001-3" ]; then
24			echo "Signature of checksum partition is wrong, bailing."
25			return 0
26		fi
27		if [ "$checksum" != "00000000" ]; then
28			echo "Checksum is set, zeroing."
29			# zero out checksum
30			dd if=$zeroes of=$tmpfile conv=notrunc bs=1 seek=0 count=4 2>/dev/null
31			# zero out bytecount to be checksummed
32			dd if=$zeroes of=$tmpfile conv=notrunc bs=1 seek=60 count=4 2>/dev/null
33			mtd write $tmpfile $partname
34		else
35			echo "Checksum is already zero, nothing to do."
36		fi
37	;;
38	rt-n56u)
39		echo "Board is ASUS RT-N56U, replacing uImage header..."
40		local firmware_mtd=$(find_mtd_part firmware)
41		local rootfs_mtd=$(find_mtd_part rootfs)
42		local rootfs_data_mtd=$(find_mtd_part rootfs_data)
43		local rootfs_len=$(grep \"rootfs\" /proc/mtd | awk -F' ' '{print "0x"$2}')
44		local rootfs_data_len=$(grep \"rootfs_data\" /proc/mtd | awk -F' ' '{print "0x"$2}')
45		local offset=$(echo "$rootfs_len $rootfs_data_len 0x40" | awk -F' ' '{printf "%i",$1-$2-$3}')
46		local signature=$(dd if=$rootfs_mtd skip=$offset bs=1 count=4 2>/dev/null | hexdump -v -n 4 -e '1/1 "%02x"')
47		if [ "$signature" = "27051956" ]; then
48			dd conv=notrunc if=$rootfs_mtd skip=$offset of=$firmware_mtd bs=1 count=64 2>/dev/null
49		fi
50	;;
51	esac
52
53	return 0
54}
55
56boot_hook_add preinit_main do_checksumming_disable
57