[alifarrukh]

I am trying to unbrick router for past 2 days,but still cannot unbrick it.Problem started when I was web upgrading and in middle of updating my pc crashed.Now power led is on and all other lights are constantly blinking together.

I have tried usb to ttl 232,but couldn't get anything past green unblinking cursor.I tried using putty,tftp,serial communicator all coudn't respond to router.On usb to ttl device gnd and rx light are lit,and when router powers on only tx led starts blinking, gnd and rx remains lit.There is no way to know what is happening.

Have tried another pc,resoldering wire again and installing driver without any success.
Have already given up on 741nd v4 after multiple unsuccessful unbricking attempts now I think this router is also dead

[alifarrukh]

Can anyone tell me what should I do ?

[ian5142]

Hello,
I have debricked both my 841nd and my 1043nd using the serial method. You may want to try switching the TX and RX ones. If the settings are correct and the router is plugged in, click the Power button to turn on the router and you should see it trying to boot. Try and click the spacebar (possibly some other key, read the text). Then start a tftp client and serve the router an older dd-wrt build that you know works. Wait until it fully boots up, don't interrupt it.

Instructions:
http://www.dd-wrt.com/phpBB2/viewtopic.php?p=887168
http://dd-wrt.com/wiki/index.php/Serial_Recovery

You need to buy a device such as this: https://www.amazon.ca/niceeshop-PL2303HX-RS232-Module-Converter/dp/B00F167PWE/ref=sr_1_1?ie=UTF8&qid=1469132227&sr=8-1&keywords=usb+to+ttl+module

[alifarrukh]

[ian5142]

Check the chip version and make sure you install the driver, it is one of the few drivers that Windows 7 and probably higher versions can not find.

http://www.prolific.com.tw/US/ShowProduct.aspx?p_id=225&pcid=41

[tou.manokat@gmail.com]

I have also unbricked my 841ND v8 and 1043nd v1 both with serial and TFTPD methods, with TFTPD being the faster. You can try this method, but change the factory recovery file name according to your router model and version.
http://www.dd-wrt.com/phpBB2/viewtopic.php?t=301877&highlight=

[LudwigFerdinand]

is there any chance I can hardbrick my router even if the TFTP ? if I only install the firmware for the TFTP the risk still exists ?

[ian5142]

Hello,
There is always a risk of bricking even with TFTP, but it is the safer of the 2 and much quicker. I just use Serial to see what is going on in the router and then use TFTP to actually debrick it. The serial output on my screen will tell me when the router can be unplugged and set up elsewhere.

My suggestion, get back to stock first than go to DD-WRT or OpenWRT.

[alifarrukh]

Right now I finally got router to output on putty screen after turning it on.Here is the log.it keeps on repeating this log on loop.Now What to do next It doesn't allow me to type tpl.

U-boot AP123


DRAM: 32 MB
id read 0x100000ff
Flash: 4 MB
Using default environment

In: serial
Out: serial
Err: serial
Net: ag934x_enet_initialize...
wasp reset mask:c03300
WASP ----> S27 PHY
file: ag934x.c,line: 180==: set LAN&WAN SWAP. --debug by HouXB
GMAC: cfg1 0x5 cfg2 0x7114
eth0: ba:be:fa:ce:08:41
s27 reg init
athrs27_phy_setup ATHR_PHY_CONTROL 4: 0x1000
athrs27_phy_setup ATHR_PHY_SPEC_STAUS 4: 0x10
eth0 up
WASP ----> S27 PHY
file: ag934x.c,line: 180==: set LAN&WAN SWAP. --debug by HouXB
GMAC: cfg1 0xf cfg2 0x7214
eth1: ba:be:fa:ce:08:41
s27 reg init lan
ATHRS27: resetting s27
ATHRS27: s27 reset done
athrs27_phy_setup ATHR_PHY_CONTROL 0: 0x1000
athrs27_phy_setup ATHR_PHY_SPEC_STAUS 0: 0x10
athrs27_phy_setup ATHR_PHY_CONTROL 1: 0x1000
athrs27_phy_setup ATHR_PHY_SPEC_STAUS 1: 0x10
athrs27_phy_setup ATHR_PHY_CONTROL 2: 0x1000
athrs27_phy_setup ATHR_PHY_SPEC_STAUS 2: 0x10
athrs27_phy_setup ATHR_PHY_CONTROL 3: 0x1000
athrs27_phy_setup ATHR_PHY_SPEC_STAUS 3: 0x10
eth1 up
eth0, eth1
is_auto_upload_firmware=0
Autobooting in 1 seconds
## Booting image at 9f020000 ...
Uncompressing Kernel Image ... ERROR: LzmaDecode.c, 543

Decoding error = 1
LZMA ERROR 1 - must RESET board to recover

U-Boot 1.1.4 (Jul 24 2014 - 17:19:52)

[alifarrukh]

[ian5142]

Just keep clicking tpl with 3 fingers when the router is booting. It does work. It does not look hopeful as it says must reset board to recover. I was getting kernel panic errors and then the router would reboot.

I would still try to interrupt the boot sequence and get access to the shell, then try a tftpd command.

[alifarrukh]

Router output on putty is below.Have also opened solar wind tftp.


U-Boot 1.1.4 (Jul 24 2014 - 17:19:52)

U-boot AP123

DRAM: 32 MB
id read 0x100000ff
Flash: 4 MB
Using default environment

In: serial
Out: serial
Err: serial
Net: ag934x_enet_initialize...
wasp reset mask:c03300
WASP ----> S27 PHY
file: ag934x.c,line: 180==: set LAN&WAN SWAP. --debug by HouXB
GMAC: cfg1 0xf cfg2 0x7114
eth0: ba:be:fa:ce:08:41
s27 reg init
athrs27_phy_setup ATHR_PHY_CONTROL 4: 0x1000
athrs27_phy_setup ATHR_PHY_SPEC_STAUS 4: 0x10
eth0 up
WASP ----> S27 PHY
file: ag934x.c,line: 180==: set LAN&WAN SWAP. --debug by HouXB
GMAC: cfg1 0xf cfg2 0x7214
eth1: ba:be:fa:ce:08:41
s27 reg init lan
ATHRS27: resetting s27
ATHRS27: s27 reset done
athrs27_phy_setup ATHR_PHY_CONTROL 0: 0x1000
athrs27_phy_setup ATHR_PHY_SPEC_STAUS 0: 0x10
athrs27_phy_setup ATHR_PHY_CONTROL 1: 0x1000
athrs27_phy_setup ATHR_PHY_SPEC_STAUS 1: 0x10
athrs27_phy_setup ATHR_PHY_CONTROL 2: 0x1000
athrs27_phy_setup ATHR_PHY_SPEC_STAUS 2: 0x50
athrs27_phy_setup ATHR_PHY_CONTROL 3: 0x1000
athrs27_phy_setup ATHR_PHY_SPEC_STAUS 3: 0x10
eth1 up
eth0, eth1
is_auto_upload_firmware=0
Autobooting in 1 seconds

Typing tpl

wasp>
wasp> tpl
Unknown command 'tpl' - try 'help'

Now typing printenv

wasp> printenv
bootargs=console=ttyS0,115200 root=31:02 rootfstype=squashfs init=/sbin/init mtdparts=ath-nor0:128k(u-boot),1024k(kernel),2816k(rootfs),64k(config),64k(art)
bootcmd=bootm 0x9f020000
bootdelay=1
baudrate=115200
ethaddr=0xba:0xbe:0xfa:0xce:0x08:0x41
ipaddr=192.168.1.111
serverip=192.168.1.100
dir=
bc=ap123
lu=tftp 0x81000000 ${dir}u-boot.bin&&erase 0x9f000000 +$filesize;cp.b $fileaddr 0x9f000000 $filesize
lf=tftp 0x81000000 ${dir}${bc}-squashfs&&erase 0x9f120000 +$filesize;cp.b $fileaddr 0x9f120000 $filesize
stdin=serial
stdout=serial
stderr=serial
ethact=eth0

Environment size: 565/65532 bytes
wasp>


When I trype in tftpboot 0x81000000 wr841nv8_en_3_15_9_up_boot(140724).bin.I get following



wasp> tftpboot 0x81000000 wr841nv8_en_3_15_9_up_boot(140724).bin
enet1 port2 up
dup 1 speed 1000
Using eth1 device
TFTP from server 192.168.1.100; our IP address is 192.168.1.111
Filename 'wr841nv8_en_3_15_9_up_boot(140724).bin'.
Load address: 0x81000000
Loading: T T T
Retry count exceeded; starting again
eth0 link down



So how do i transfer firmware to the router?I have plugged ethernet cable to lan port of router

[ian5142]

When it is looking for a tftp file, click upload on the tftp program on your computer. You may want to try a shorter name like firmware.bin

It times out after 3 tries so you need to click enter in one screen and then click upload on the other screen at just about the same time.

[understracker]

You can easily debrick your 841ndv8 using the build in tftp client in the bootloader. The tftp server must run on your pc and have ip address 192.168.0.66

see here: https://wiki.openwrt.org/toh/tp-link/tl-wr841nd#tftp_recovery_via_bootloader_for_v8_v9_v10_v11

1. download ftp://ftp.dd-wrt.com/betas/2016/04-25-2016-r29519/tplink_tl-wr841ndv8/factory-to-ddwrt.bin at your desktop
2. rename it to wr841nv8_tp_recovery.bin
3. download http://tftpd32.jounin.net/download/tftpd32.452.zip at your desktop
4. unzip tftpd32.452.zip eg in folder tftpd32.452 using right click->extract to
5. put wr841nv8_tp_recovery.bin aside tftpd32.exe in folder tftpd32.452
6. change your Ethernet adapter ipv4 address to static addess 192.168.0.66/subnet mask 255.255.255.0/leave gateway and dns void
7. connect the lan1 port of you router to pc's ethernet port
8. start tftpd32.exe and on server interface select your Ethernet nic which should have ip 192.168.0.66. If you have a firewall you may need to disable it or put tftp32 to its exception list.
9. fire up your router WHILE pressing reset for three seconds
10. you should see an incoming connection in the tftp32 gui. if not, something went wrong. Repeat the above process more carefully.
11. when download completes, your router shall reboot
12. restore the Ethernet NIC address to automatic assignment
13. you must be able to reach you shine new dd-wrt at 192.168.1.1

you can also watch this video: https://www.youtube.com/watch?v=0k1sxwX5pMk

remember the recovery image filename is wr841nv8_tp_recovery.bin for v8.

[tou.manokat@gmail.com]

I am attaching the exact stock file that I used when I unbricked my 841ND v8. Check the attachment.
Before knowing there was an alternative to serial unbricking I had used a Nokia DKU-5 to unbrick it when it got bricked the first time.

From the serial console log you provided it would appear that your 841 v8.4 is expecting a TFTPD IP of
192.168.1.100 because you have executed these env setting operands:

setenv ipaddr 192.168.1.111
setenv serverip 192.168.1.100

The above commands are actually optional, you can skip those and the router will expect a firmware file from TFTPD IP 192.168.0.66. If you put those commands, then set your LAN IP of your computer to 192.168.1.100 and put the stock firmware wr841nv8_en_3_15_9_up_boot(140724).bin in the TFTPD folder. You need a TFTPDaemon or server and not a TFTP client. Your computer will work as a server to send the firmware file to the router.