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Topic: [HowTo] TP-LINK WR841ND V7.2 Unbricked and Original Firmware

The content of this topic has been archived between 30 Mar 2018 and 5 May 2018. There are no obvious gaps in this topic, but there may still be some posts missing at the end.

Okay. So, I have bricked mine (tl-wr841n). I read this post, and got myself a dku-5 but it only has 3 wires (blue, red, orange). I found this pdf (http://www.neolics.com/pdfs/dku-5.pdf), which says that the one with the highest voltage will be the tx (blue). The orange is ground, and that leaves the red to be rx. When I connect with this arrangement, it shows me a blank black screen. Any other combination gives a somewhat half-eligible and half-gibberish output, but either hangs my computer, or gives me a blue screen of death.

I went looking for a Ca42 (as it unbricked omiez's) in our local market, but couldn't find it. Because of my location and budget, internet shopping websites (eBay, Amazon, etc.) are out of the question.

Any help would be greatly appreciated, because I am a newbie to electronics and am completely lost.


Edit: The blue wire gives out reading 3.5 volts, the red dances around from 0.24 to 0.28

(Last edited by g718669 on 19 Aug 2013, 18:28)

Hi @ all!

I have a WR841nd V8.2 with failed Firmware update

Now i connect a serial cable with TX RX and GND to the TP Link pins inside but I'm getting strange characters..

Baud is 115200, N 8 1 - Flow Control disabled

Can anyone help me?

what serial interface? you know it's 3.3v ttl serial and not "classic" rs232?

I have a classic RS232 - that won't work?

Hello guys!

I've got TL-WR841N v7.2 with ART partition blanked (it was erased with the flash programmer). Can someone copy an art partition from similar device?

It can be done via OpenWRT.
cat /proc/mtd
cat /dev/mtdX > /tmp/art.bin
Instead of X put the ART partition number (reported by first command)

Hello everybody. Also me, unfortunately I made a mistake in uploading firmware to my router WR841N v.8.4.
I read this interesting guide but I could not upload the right firmware.
For convenience I have included three wires at the GND - RX - TX as  drawing:
PunBB bbcode test
The cable is soldered to the GND in white / green, one is brown while the TX and RX is Blue.

I bought the serial cable and Nokia DKU5 I cut it. I then divided the cables are:

White
Black
Red
Blue
Yellow

PunBB bbcode test

I connected the white wire with the wire white / green, then I connected the brown wire with the red wire and finally the blue wire with the blue.

I launched putty and inserted COM5 (serial port) 115200 8N1

I started the router and I saw this:

PunBB bbcode test

I seem to have done everything as suggested by the guide but I do not understand why it does not work.
Can anyone help me? Where I'm wrong?
thanks in advace.

(Last edited by rcaruccio on 16 Mar 2014, 00:11)

rcaruccio wrote:

Hello everybody. Also me, unfortunately I made a mistake in uploading firmware to my router WR841N v.8.4.
I read this interesting guide but I could not upload the right firmware.
For convenience I have included three wires at the GND - RX - TX as  drawing:
PunBB bbcode test
The cable is soldered to the GND in white / green, one is brown while the TX and RX is Blue.

I bought the serial cable and Nokia DKU5 I cut it. I then divided the cables are:

White
Black
Red
Blue
Yellow

PunBB bbcode test

I connected the white wire with the wire white / green, then I connected the brown wire with the red wire and finally the blue wire with the blue.

I launched putty and inserted COM5 (serial port) 115200 8N1

I started the router and I saw this:

PunBB bbcode test

I seem to have done everything as suggested by the guide but I do not understand why it does not work.
Can anyone help me? Where I'm wrong?
thanks in advace.

Good day to you all.

Unfortunately I also made the mistake uploading a wrong DD-WRT Firmware to my router WR841ND v8.2.
After reading most of the comments and the guide lines, I'm not sure if I should try it out on my router, because many of you posted errors at PuTTY
Are there any confirmed successfully restored to factory with the same guide lines from freddyarenas regarding to WR841ND v8.2?
Is it necessary to solder the GND, RX & TX to the mainboad or is it enough to just simply attach the wire?

@freddyarenas: Thank you for the guide lines. Before I buy the necessary cable or brake my router, I just want to be sure, if there is anyone who managed to solve a similar problem.

Kind regards,
Thank you

There is no one that can help us understand how the Unbricked WR841N ver.8.4?

omiez wrote:

Hello Wclemo

Yes I managed first to unbrick with Ca-42 cable and later to flash dd-wrt using web flash image from Attitude directory. Now running 12.09 beta and seems to work without problems.

Thank you very much for your answer.

Stay tuned so if we have problems we can help us out.

Hi fellow, one cuestion, is your cable labeled with the serial wt048000317? i have one of these, and i ve readed that all the cables with this serial are all the same, i have one with this serial and model Nº kq u8a, and in other forums said that its like the nokia cable, i have one problem here, my cable has 4 colors that i cant figure it out how to conect to the pins of my wr841n 7.2, the colors are yellow, blue, green and white, wich one is it, can you explain me please? thanks in advance!

rcaruccio wrote:

There is no one that can help us understand how the Unbricked WR841N ver.8.4?

there`s a part  in this wiki that it can help you http://wiki.openwrt.org/toh/tp-link/tl-wr841nd

All great info AND if you have time and patience and are okay that after all is said and done you might still fail -- go for it.
FOR THE REST OF US -- Know that you can buy a new WR841N(D) for LESS than $20 on Amazon today.
There is also a similar DLink 615 that can be loaded with WRT.

I "bricked" mine yesterday - tried the various resets  and finally ended up here....

NOW a question:  Why not make WRT more resistant to bad or wrong version uploads? To interrupted uploads?

Simple stuff -- Checksum the would-be new image - and the image should contain identifiers saying which models it is intended for.  Allow an override for the adventurous and/or foolish, but otherwise reject a "bad" image file.

Also,  Leave some bootstrap loaded code untouched - a bootstrap that can communication via the Ethernet port.

That bootstrap will check whether a reset button is "in" - if so it will go to emergency mode - instead of booting the "real" router code.

These two items would make the upgrade process almost foolproof - plus there would always be a recovery path even if I was so foolish as to force a bad image.

Hy

I'm new, and my English is not perfect, hope you will understand:)

I have a TP- Link wr841N v8.2... from the stock firmware I went to openwrt (or superwrt, I don't remind that exactly.) It was slow and when I changed some setting, the connection was lost some times.

I think I deleted, or disabled the eth0 or what, where is listed the wifi in the menu, where I have to fill the ppp user and password to make a connection to the internet.

Sometimes it connects to the router by 192.168... sometimes not. Now I can't reach it.My second LED starts blinking two times, a little pause (1 second or 2), and again two blinks, pause, two blinks. Even when I power on, after reset... always blink this way, I can't tenet, tftp it on LAN WAN...now I have a USB 2.0 to UART TTL 6PIN Connector Module Serial Converter CP2102

The driver is installed for it, I have win 8.1 x64. I downloaded the putty, I connected the 3 pin, in the correctly to the pouters mainboard. On my USB module, there are two LEDs. One red, for the power, and one green, for data. There are ON, but when I power on the router, the data LED indicator on the USB turns off. I can't telnet the router. I changed my PCs IP to 192.168.1.2, the router is x.x.1.1, but nothing. On the puttys window, nothing happen. It's empty.Can somebody tells me what and how I have to do to reach it, and put it back in original? Or it's dead? I want to unbick it, but I don't now if the order is important, when I plug in the cables, when I open the apps on pc? Or it doesn't matter?

Guys, help me please sad

try to reverse tx with rx pins.

never connect vcc pin to anything

order of powering/connection/open putty should not change result..

putty settings for serial?

My router is back, finally I find out what and how I have to do. Thank you

(Last edited by alex_mok on 11 May 2014, 04:47)

Hello everyone.
I'm trying to unbrick a TP-LINK WR740N. I have a problem when trying to open the connection in Putty. The screen goes black and not even see symbols.
Any idea what may be happening? maybe the router is dead?

I think I've configured the connection properly: 115200 8N1, no flow control

(Last edited by pata on 30 Jun 2014, 01:57)

omiez wrote:

Hello

Unfortunately my router is booting again and again. There was an electrical drop during flash operation. I was trying to install dd-wrt firmware.

I found your guide but I don't know which firmware I must flash. The link to the firmware in this guide does not work but anyway I was flashing dd-wrt and not open-wrt.

Can anybody please tell me which firmware I can flash via serial?

I ordered a Nokia ca-42 cable. I think it is ok for this job.


EDIT:
Problem solved with CA-42 cable.



I want to install OPEN-WRT now on my TL-WR841ND V7.2 can anyone tell me if this router is supported cause i can´t find firmware for v7.2 ?

can u plz describe step by step with pictures that u solved your problem?
i have same v7.2 tplink wr841n and im stuck at all leds flashing after every 4 seconds.......thanks in advance

hello all i have a little probleme, i use the ttl cable, when i start putty and i type "tpl" nothing is show ( like i type nothing) i cannot stop the reboot loop :\

that what it show :
#### TAP VALUE 1 = 7, 2 = 8
32 MB
id read 0x100000ff
flash size 4194304, sector count = 64
Flash:  4 MB
Using default environment

eth0: 00:03:7f:09:0b:ad
eth0 up
No valid address in Flash. Using fixed address
: cfg1 0xf cfg2 0x7214
eth1: 00:03:7f:09:0b:ad
ATHRS26: resetting s26
ATHRS26: s26 reset done
eth1 up
eth0, eth1
Autobooting in 1 seconds
## Booting image at 9f020000 ...
   Uncompressing Kernel Image ... Error: Bad gzipped data
GUNZIP ERROR - must RESET board to recover

Resetting...

U-Boot 1.1.4 (Jan 30 2012 - 18:27:20)

AP93 (ar7240) U-boot
DRAM:
sri
#### TAP VALUE 1 = 7, 2 = 8
32 MB
id read 0x100000ff
flash size 4194304, sector count = 64
Flash:  4 MB
Using default environment

In:    serial
Out:   serial
Err:   serial
Net:   ag7240_enet_initialize...
No valid address in Flash. Using fixed address
: cfg1 0xf cfg2 0x7014
eth0: 00:03:7f:09:0b:ad
eth0 up
No valid address in Flash. Using fixed address
: cfg1 0xf cfg2 0x7214
eth1: 00:03:7f:09:0b:ad
ATHRS26: resetting s26
ATHRS26: s26 reset done
eth1 up
eth0, eth1
Autobooting in 1 seconds

It's normal you do not see it.. try typing very fast!

Hello,

I have a WR841N v8.4 and I can't upload the firmware from TFTP. I do a ping from the ROUTER to the PC and the PC tothe ROUTER and there is no response, any idea?

Thanks and best regards,

Adelmo

Can someone help me by debricking my WA7510N V1 same as WR841ND V5
I tried mtd -r write firmware.bin linux in WA7510N but it shows failed to erase mtd block,then after sometime i turned of my router then when i turned i on it's Power light lights up and LAN light goes on and off continously and LAN connection to thr laptop also goes on and of.
I have buyed CP2102 USB 2.0 to TTL UART SERIAL CONVERTER - Arduino, ARM and other MCU Ebay link(http://www.ebay.in/itm/CP2102-USB-2-0-to-TTL-UART-SERIAL-CONVERTER-Arduino-ARM-and-other-MCU-/111628421203?)
So can someone tell me the serial pinouts on WA7510N.So i can connect it to CP2102.And flash the router with the methods as freddyarenas described

Friend i solved the problem myself as freddy does i do but instead of the openwrt firmware i have directly uploaded the TP-Link firmware.And now my router works fine.

Hey I think my problem is best here:

I somehow managed to fully brick my WR841ND V7.2:

So I get no signal from the serial/UART and the LED's are blinking slow, and no power on the ethernet.

As the 7.2 has no UART, did anybody has an idea if there is a solution to bring Uboot back or if there is an other deeper failsave?


Only to be clear for all, my usb2serial is working and I know how to use it.

freddyarenas wrote:

Hello great community thanks for that great website wiki and happy new year for all!

T serial connection you get something like this:

AP93 (ar7240) U-boot
DRAM:  
sri
#### TAP VALUE 1 = 9, 2 = 9
32 MB
id read 0x100000ff
flash size 4194304, sector count = 64
Flash:  4 MB
Using default environment

In:    serial
Out:   serial
Err:   serial
Net:   ag7240_enet_initialize...
No valid address in Flash. Using fixed address
: cfg1 0xf cfg2 0x7014
eth0: 00:03:7f:09:0b:ad
eth0 up
No valid address in Flash. Using fixed address
: cfg1 0xf cfg2 0x7214
eth1: 00:03:7f:09:0b:ad
ATHRS26: resetting s26
ATHRS26: s26 reset done
eth1 up
eth0, eth1
Autobooting in 1 seconds

now Type "tpl" (without the quotes) to get to the Uboot console prompt.

2. Open your TFTP server and put "openwrt-ar71xx-generic-tl-wr841nd-v7-squashfs-factory.bin" image into your server current directory and rename it if you want: I renamed to openwrt.bin.

Hook your computer into the switch port and configure the IP for example: 192.168.1.2

Now we need to set router and server IP addresses (here named ROUTERIP and SERVERIP, substitute these with the real IP addresses).

Type in the console:

setenv ipaddr ROUTERIP
setenv serverip SERVERIP
printenv

example:

setenv ipaddr 192.168.1.1
setenv serverip 192.168.1.2
printenv

3. Double check that the output of printenv lists the IP addresses you just set. Now we can load the firmware over TFTP with "tftpboot 0x80000000 openwrt.bin":




Thanks for this great firmware is very stable.


Regards,

Freddy Arenas


Hi,
I have wr841nd ver. 8.0 and I can not make settings  using  tplink.net. Now I am trying a firmware reset. My router IP is 192.168.0.1
I do not understand what ip should I use for :SERVERIP:

Thank you.
L.E. I read twice those instructions and it worked( after I changed LAN  with WAN port to conect router to PC) .

(Last edited by alexm1 on 10 Oct 2015, 16:59)

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