2019-02-11-upgrade-flash-chip-tplink-tl-wr840n-4mb-to-8mb

create_new_firmware.sh

set -e
flash_size_in_MB=8
sysupgrade_OpenWRT="openwrt-18.06.1-ramips-mt76x8-tl-wr840n-v5-squashfs-sysupgrade.bin"
art_file="upload_openwrt_art.bin"
boot_loader="upload_openwrt_mtd0.bin"

sysupgrade_OpenWRT_size=$(wc -c $sysupgrade_OpenWRT | cut -f 1 -d " ")
art_file_size=$(wc -c $art_file | cut -f 1 -d " ")
boot_loader_size=$(wc -c $boot_loader | cut -f 1 -d " ")


echo "sysupgrade_OpenWRT_size: " $sysupgrade_OpenWRT_size
echo "art_file_size: " $art_file_size
echo "boot_loader_size: " $boot_loader_size

padcount=$(($flash_size_in_MB * 1024 * 1024 - $boot_loader_size - $art_file_size - $sysupgrade_OpenWRT_size))

echo " Write boot loader"
dd if=$boot_loader bs=512 >> "${sysupgrade_OpenWRT}_dump".bin
echo "Write firmware"
dd if=$sysupgrade_OpenWRT bs=512 >> "${sysupgrade_OpenWRT}_dump".bin
echo "Write padding FF"
dd if=/dev/zero ibs=1 count="$padcount" | tr "\000" "\377" >> "${sysupgrade_OpenWRT}_dump".bin
echo "Write art partition"
dd if=$art_file bs=512 >> "${sysupgrade_OpenWRT}_dump".bin

firmware_bad.log

fixed-partitions partitions found on MTD device spi0.0
Creating 3 MTD partitions on "spi0.0":
0x000000000000-0x000000020000 : "boot"
0x000000020000-0x0000003f0000 : "firmware"
2 tplink-fw partitions found on MTD device firmware
0x000000020000-0x00000017d048 : "kernel"
0x00000017d048-0x0000003f0000 : "rootfs"
mtd: device 3 (rootfs) set to be root filesystem
1 squashfs-split partitions found on MTD device rootfs
0x0000003b0000-0x0000003f0000 : "rootfs_data"
0x0000003f0000-0x000000400000 : "factory"

m25p80 spi0.0: s25fl064k (8192 Kbytes)

VFS: Mounted root (squashfs filesystem) readonly on device 31:3.
Freeing unused kernel memory: 208K
This architecture does not have kernel memory protection.
init: Console is alive
init: - watchdog -
random: fast init done
kmodloader: loading kernel modules from /etc/modules-boot.d/*
kmodloader: done loading kernel modules from /etc/modules-boot.d/*
init: - preinit -
rt3050-esw 10110000.esw: link changed 0x00
random: procd: uninitialized urandom read (4 bytes read)
jffs2: Too few erase blocks (4)  --> Your image is probably too big, leaving not enough space for jffs2.
mount_root: failed to mount -t jffs2 /dev/mtdblock4 /tmp/overlay: Invalid argument
mount_root: overlay filesystem has not been fully initialized yet
mount_root: switching to jffs2 overlay
mount_root: switching to jffs2 failed - fallback to ramoverlay
urandom-seed: Seed file not found (/etc/urandom.seed)

firmware_bad_no_overlay.log

root@OpenWrt:~# df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/root                 2.3M      2.3M         0 100% /rom
tmpfs                    29.5M    532.0K     29.0M   2% /tmp
tmpfs                    29.5M     56.0K     29.5M   0% /tmp/root
overlayfs:/tmp/root      29.5M     56.0K     29.5M   0% /
tmpfs 

firmware_good.log

root@OpenWrt:~# df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/root                 2.3M      2.3M         0 100% /rom
tmpfs                    29.5M    540.0K     29.0M   2% /tmp
/dev/mtdblock4            4.1M    304.0K      3.8M   7% /overlay
overlayfs:/overlay        4.1M    304.0K      3.8M   7% /
tmpfs                   512.0K         0    512.0K   0% /dev
root@OpenWrt:~# 
root@OpenWrt:~# cat /proc/mtd
dev:    size   erasesize  name
mtd0: 00020000 00010000 "boot"
mtd1: 007a0000 00010000 "firmware"
mtd2: 0015d05b 00010000 "kernel"
mtd3: 00642fa4 00010000 "rootfs"
mtd4: 00410000 00010000 "rootfs_data"
mtd5: 00010000 00010000 "config"
mtd6: 00030000 00010000 "factory"

flash_partition.md

parameter	Description
flash_size_in_MB	new flash chip capacity
sysupgrade_OpenWRT	OpenWRT image (firmware)
art_file	ART partion from original flash, the last 64k block of the chip no matter what the chip size.
boot_loader	bootloader, the first 128kB from original flash
Output firmware	sysupgrade_OpenWRT_dump.bin, you can use this to program your new flash chip

Original_vs_Mod_Chip.md

Description	Original	Mod
flash	GigaDevice GD25Q32B (4MB)	Winbond GD25Q64CSIG (8MB)
firmware	TL-WR840N(VN)_V5_170517	openwrt-18.06.1-ramips-mt76x8-tl-wr841n-v13-squashfs-sysupgrade

WR841Nv13_vs_WR840Nv5.md

Description	TP-LINK TL-WR841N v13.x	TP-LINK TL-WR840N v5
CPU	MediaTek MT7628NN (580MHz)	MediaTek MT7628NN @575MHz
RAM	Winbond W9751G6JB-25 (64MB)	ESMT M14D5121632A (64MB)
Flash	GigaDevice GD25Q64CSIG (8MB)	GigaDevice GD25Q32B (4MB)