target/linux/ramips/rt3883/base-files/lib/preinit/04_handle_checksumming

   1 # Netgear WNCE2001 has does a checksum check on boot and goes into recovery
   2 # tftp mode when the check fails.  Initializing the JFFS2 partition triggers
   3 # this, so we make sure to zero checksum and size to be checksummed before
   4 # that happens, so this needs to run very early during boot.
   5
   6 do_checksumming_disable() {
   7         . /lib/functions.sh
   8
   9         local board=$(board_name)
  10
  11         case "$board" in
  12         asus,rt-n56u)
  13                 echo "Board is ASUS RT-N56U, replacing uImage header..."
  14                 local firmware_mtd=$(find_mtd_part firmware)
  15                 local rootfs_mtd=$(find_mtd_part rootfs)
  16                 local rootfs_data_mtd=$(find_mtd_part rootfs_data)
  17                 local rootfs_len=$(grep \"rootfs\" /proc/mtd | awk -F' ' '{print "0x"$2}')
  18                 local rootfs_data_len=$(grep \"rootfs_data\" /proc/mtd | awk -F' ' '{print "0x"$2}')
  19                 local offset=$(echo "$rootfs_len $rootfs_data_len 0x40" | awk -F' ' '{printf "%i",$1-$2-$3}')
  20                 local signature=$(dd if=$rootfs_mtd skip=$offset bs=1 count=4 2>/dev/null | hexdump -v -n 4 -e '1/1 "%02x"')
  21                 if [ "$signature" = "27051956" ]; then
  22                         dd conv=notrunc if=$rootfs_mtd skip=$offset of=$firmware_mtd bs=1 count=64 2>/dev/null
  23                 fi
  24         ;;
  25         esac
  26
  27         return 0
  28 }
  29
  30 boot_hook_add preinit_main do_checksumming_disable