TL-WR941ND back to original firmware

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dvd741
DD-WRT Novice


Joined: 11 Feb 2011
Posts: 3

PostPosted: Fri Feb 11, 2011 2:53    Post subject: TL-WR941ND back to original firmware Reply with quote
I tried resetting the TL-WR941ND back to it's original firmware using the reverse files posted here on the forum. No succes.

I thought about using dd-wrt then, since turning back doesn't seem to be possible, but after each power-interrupt / reboot all setting are lost...

Is there any other way to reverse the firmware back to the original one besides using a so-called 'Serial cable'? - I do not own one of those...

If not there is no other solution for me but to buy a new router..

Please advise Sad
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LOM
DD-WRT Guru


Joined: 28 Dec 2008
Posts: 7214

PostPosted: Fri Feb 11, 2011 3:38    Post subject: Re: TL-WR941ND back to original firmware Reply with quote
dvd741 wrote:


I thought about using dd-wrt then, since turning back doesn't seem to be possible, but after each power-interrupt / reboot all setting are lost...



I guess you have WR941ND v3.2 with the Intel flash chip which dd-wrt can't write.
Therefore it can't save settings and can't write any update files to flash.

Serial console is your only chance to debrick it.

_________________
I'm on a whiskey diet, lost 3 days already
dvd741
DD-WRT Novice


Joined: 11 Feb 2011
Posts: 3

PostPosted: Fri Feb 11, 2011 4:22    Post subject: Reply with quote
And where can i find the manual on that exactly?
(I don't have a cable of any kind & am an absolute noob @ hardware stuff like connecting the cable with the right connectors)

And is there any chance the intel chip will become writeable in the next days/weeks/months?
dvd741
DD-WRT Novice


Joined: 11 Feb 2011
Posts: 3

PostPosted: Fri Feb 11, 2011 11:48    Post subject: Reply with quote
I found this link
http://www.dd-wrt.com/wiki/index.php/Serial_port_pinouts

Although, I still think this is risky business for me... Perhaps i will give it a try, is any USB-Phone cable suitable to work as serial connector?

Which commands should I enter in the (Hyperterminal? - if I Googled correctly) to reinstall the factory firmware?
nebbia88
DD-WRT User


Joined: 08 Mar 2010
Posts: 173

PostPosted: Fri Feb 11, 2011 17:33    Post subject: Reply with quote
http://lmgtfy.com/?q=tp-link+serial+cable+tutorial
erreterr
DD-WRT Novice


Joined: 15 Oct 2010
Posts: 39

PostPosted: Mon Apr 04, 2011 21:08    Post subject: Reply with quote
The only chance to revive the TL-WR941 router with Intel Flash chip is via Serial port. For serial port pinouts you can find plenty of pictures. For cable use Nokia Ca-42. cable or something like that. Files you can find on google. Just copy and paste the complete filename. Only 2 files are needed.

1. Start the board:

> U-Boot 1.1.4 (Jun 18 2009 - 15:08:27)
>
> AP81 (ar7100) U-boot
> DRAM:
> sri
> 32 MB
> id read 0x100000ff
> flash size 8MB, sector count = 128
> Flash: 8 MB
> Using default environment
>
> In: serial
> Out: serial
> Err: serial
> Net: ag7100_enet_initialize...
> No valid address in Flash. Using fixed address
> eth0: 00:03:7f:09:0b:ad
> eth0 up
> eth0
> Autobooting in 1 seconds

2. Tpye 'tpl' here, so you can go into the CLI of the bootloader.

> Autobooting in 1 secondsar7100>
> ar7100>

3. Setup the IP addresses according to your setup

> ar7100> setenv serverip 192.168.1.254; setenv ipaddr 192.168.1.1

4. Load the attached initramfs image via TFTP, and boot that with the following
command:

> ar7100> tftp 0xa0800000 openwrt-ar71xx-generic-tl-wr941nd-v3-initramfs-uImage.bin; bootm 0xa0800000
> set link to 100M full by lqm.
> dup 1 speed 100
> Using eth0 device
> TFTP from server 192.168.1.254; our IP address is 192.168.1.1
> Filename 'openwrt-ar71xx-generic-tl-wr941nd-v3-initramfs-uImage.bin'.
> Load address: 0xa0800000
> Loading: #################################################################
> #################################################################
> #################################################################
> #################################################################
> #################################################################
> #################################################################
> #################################################################
> #################################################################
> #################################################################
> ###########################################################
> done
> Bytes transferred = 3297007 (324eef hex)
> ## Booting image at a0800000 ...
> Uncompressing Kernel Image ... OK
>
> Starting kernel ...

5. Wait until the kernel boots:

> Linux version 2.6.37-rc4 (juhosg@idared) (gcc version 4.3.3 (GCC) ) #3 Wed Dec 1 18:52:15 CET 2010
> bootconsole [early0] enabled
> CPU revision is: 00019374 (MIPS 24Kc)
> Atheros AR9132 rev 2, CPU:400.000 MHz, AHB:100.000 MHz, DDR:400.000 MHz
> Determined physical RAM map:
> memory: 02000000 @ 00000000 (usable)
> <...>
> ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
> nf_conntrack version 0.5.0 (460 buckets, 1840 max)
> ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
> Initializing USB Mass Storage driver...
> usbcore: registered new interface driver usb-storage
> USB Mass Storage support registered.

6. Press <Enter> here.

> BusyBox v1.17.3 (2010-11-26 20:05:50 CET) built-in shell (ash)
> Enter 'help' for a list of built-in commands.
>
> _______ ________ __
> | |.-----.-----.-----.| | | |.----.| |_
> | - || _ | -__| || | | || _|| _|
> |_______|| __|_____|__|__||________||__| |____|
> |__| W I R E L E S S F R E E D O M
> KAMIKAZE (bleeding edge, r24196) ------------------
> * 10 oz Vodka Shake well with ice and strain
> * 10 oz Triple sec mixture into 10 shot glasses.
> * 10 oz lime juice Salute!
> ---------------------------------------------------
> root@OpenWrt:/#

7. Download the original firmware image into /tmp via wget.

> root@OpenWrt:/# cd tmp
> root@OpenWrt:/tmp# wget ftp://192.168.1.254:2121/openwrt/wr941nv2_en_3_11_8_up\(100609\).bin
> Connecting to 192.168.1.254:2121 (192.168.1.254:2121)
> wr941nv2_en_3_11_8_u 100% |*******************************| 3840k 00:00:00 ETA
> root@OpenWrt:/#

8. Write that into the firmware partition with the mtd command:

> root@OpenWrt:/tmp# mtd write wr941nv2_en_3_11_8_up\(100609\).bin firmware
> Unlocking firmware ...
>
> Writing from wr941nv2_en_3_11_8_up(100609).bin to firmware ...
> root@OpenWrt:/tmp#

9. Reboot the device:

> root@OpenWrt:/tmp# reboot

10. Then the board should boot into the original firmware:

> root@OpenWrt:/tmp# eth0: link down
> br-lan: port 1(lan1) entering forwarding state
> device eth0 left promiscuous mode
> device lan4 left promiscuous mode
> br-lan: port 4(lan4) entering disabled state
> device lan3 left promiscuous mode
> br-lan: port 3(lan3) entering disabled state
> device lan2 left promiscuous mode
> br-lan: port 2(lan2) entering disabled state
> device lan1 left promiscuous mode
> br-lan: port 1(lan1) entering disabled state
> lan1: link down
> Restarting system.
>
>
> U-Boot 1.1.4 (Jun 18 2009 - 15:08:27)
>
> AP81 (ar7100) U-boot
> DRAM:
> sri
> 32 MB
> id read 0x100000ff
> flash size 8MB, sector count = 128
> Flash: 8 MB
> Using default environment
>
> In: serial
> Out: serial
> Err: serial
> Net: ag7100_enet_initialize...
> No valid address in Flash. Using fixed address
> eth0: 00:03:7f:09:0b:ad
> eth0 up
> eth0
> Autobooting in 1 seconds## Booting image at bf020000 ...
> Uncompressing Kernel Image ... OK
>
> Starting kernel ...
>
> Linux version 2.6.15--LSDK-6.1.1.40 gcc version 3.4.4 #1 Tue Jun 1 15:13:49 CST 2010
> flash_size passed from bootloader = 8
> CPU revision is: 00019374
> Determined physical RAM map:
> memory: 02000000 @ 00000000 (usable)
> Built 1 zonelists
> Kernel command line: console=ttyS0,115200 root=31:2 rootfstype=squashfs init=/sbin/init
> Primary instruction cache 64kB, physically tagged, 4-way, linesize 32 bytes.
> Primary data cache 32kB, 4-way, linesize 32 bytes.
> Synthesized TLB refill handler (20 instructions).
> Synthesized TLB load handler fastpath (32 instructions).
> Synthesized TLB store handler fastpath (32 instructions).
> Synthesized TLB modify handler fastpath (31 instructions).
> ...

And read and read again the threads located here how I did serial console connection. https://forum.openwrt.org/viewtopic.php?id=18354&p=6

Procedure courtesy of Gabor Juhos from OpenWRT developing team

And the router is alive again...
bulimar
DD-WRT Novice


Joined: 17 Mar 2013
Posts: 1

PostPosted: Sun Mar 17, 2013 3:37    Post subject: TP-Link TL-WR941ND V3.2 router unbricked ! Reply with quote
Hi all,

As for many others my router got bricked after a bad flash with an Open WRT firmware.

There is no easy way to recover your TP-Link TL-WR941ND V3.2 router....

Basically you have to open the router and solder to its PCB a USB to Serial TTL RS232 cable.

Using a serial port communicator software, a TFTP server and a FTP server you can manage to push the stock firmware back into the router via the serial cable.

A good thing to do once the router is working again is to replace that stock firmware with DD-WRT build 15778. That's because the original one keeps dropping the Wi-Fi connections (at least in my case).

More details you can find on Youtube: http://youtu.be/sxVP7WGzH_A

Here are some useful links:

http://depositfiles.com/files/rrsrhvw82

http://www.ebay.ca/itm/6pin-FTDI-FT232RL-USB-to-Serial-adapter-module-USB-TO-TTL-RS232-Arduino-Cable-/400356015296?pt=LH_DefaultDomain_0&hash=item5d3713fcc0&_uhb=1#ht_2766wt_1139

http://mirrors.muarf.org/openwrt-custom/backfire/ar71xx/

http://www.tp-link.com/ca/support/download/?model=TL-WR941ND&version=V3

http://filezilla-project.org/download.php?type=server

http://solarwinds-tftp-server.en.softonic.com/download

Many thanks to all posters and good luck to those ones looking into recovering their routers.
cerdobeer
DD-WRT Novice


Joined: 13 Nov 2013
Posts: 1

PostPosted: Thu Nov 14, 2013 5:48    Post subject: Re: TP-Link TL-WR941ND V3.2 router unbricked ! Reply with quote
bulimar wrote:


More details you can find on Youtube: http://youtu.be/sxVP7WGzH_A



UPDATE:I followed these Instructions and successfully unbricked my TP-Link TL-WR941ND!!! GREAT!!

The Problem was that I didn't disabled the Windows 8 Firewall, after that everything went smoothly.

Thanks to erreterr & bulimar!!!
Wink
valdhano
DD-WRT Novice


Joined: 02 Dec 2014
Posts: 1

PostPosted: Tue Dec 02, 2014 2:46    Post subject: just ag7100_enet_initialize... why?? Reply with quote
U-Boot 1.1.4 (Sep 3 2010 - 12:15:3Cool

AP81 (ar7100) U-boot
DRAM:
sri
32 MB
id read 0x100000ff
flash size 4MB, sector count = 64
Flash: 4 MB
Using default environment

In: serial
Out: serial
Err: serial
Net: ag7100_enet_initialize...


U-Boot 1.1.4 (Sep 3 2010 - 12:15:3Cool

AP81 (ar7100) U-boot
DRAM:
sri
32 MB
...... Sad
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