How to unbrick WNR834B v1 (JTAG HELP)

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gilsonsjc
DD-WRT Novice


Joined: 12 Mar 2008
Posts: 21

PostPosted: Sat Apr 17, 2010 0:58    Post subject: How to unbrick WNR834B v1 (JTAG HELP) Reply with quote
Greetings from Brazil! Cool

I guess I have managed to brick my router (that is what I got after reading the peacock topic). The constant amber light is on and I can not ping it even setting up a static ip address.

Now I want to try the Jtag thing. First I guess I need to do a cable. I have seen on another topic that my router has those 4 connectors. Can someone tell me which cable to buy?

Here is the circuit picture (will I use that 4 pins connector for jtag?)


and I am wondering if this cable http://apple.clickandbuild.com/cnb/shop/ftdichip?productID=53&op=catalogue-product_info-null&prodCategoryID=47 could help me out solving my issue


Thank you guys
Gilson


Last edited by gilsonsjc on Sat Apr 17, 2010 11:06; edited 2 times in total
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gilsonsjc
DD-WRT Novice


Joined: 12 Mar 2008
Posts: 21

PostPosted: Sat May 29, 2010 20:33    Post subject: Reply with quote
I got the following things to try to unbrick my router:
USB to Serial port connector
RS232 - TTL
A cable to connect the router console to the RS232 - TTL

I connected all those things making sure the pins in the RS232 - TTL match the ones in the router console

RS232 - TTL
http://www.dd-wrt.com/phpBB2/files/ttl_208.jpg

Router console. Found the schema here http://oldwiki.openwrt.org/OpenWrtDocs(2f)Hardware(2f)Netgear(2f)WNR834B.html#head-4e1671a5d9186d9f786c427bd951ec6cc91567e8

Ok, please find some pictures on how I connected everthing and the set up on the windons machine.

The problem now is that after all that work, this is what I got when I tried to use tjtag
Code:

======
C:\tjtag3-0-1\Windows32>tjtag3 -probeonly

==============================================
 EJTAG Debrick Utility v3.0.1 Tornado-MOD
==============================================

Probing bus ... Done

Instruction Length set to 5

CPU Chip ID: 00000000000000000000000000000000 (00000000)
*** Unknown or NO CPU Chip ID Detected ***

*** Possible Causes:
    1) Device is not Connected.
    2) Device is not Powered On.
    3) Improper JTAG Cable.
    4) Unrecognized CPU Chip ID.

C:\tjtag3-0-1\Windows32>
==========

Can somebody please help me on how to solve this problem?

Thanks
Gilson



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redhawk0
DD-WRT Guru


Joined: 04 Jan 2007
Posts: 11563
Location: Wherever the wind blows- North America

PostPosted: Sat May 29, 2010 22:43    Post subject: Reply with quote
There is no JTAG....you can NOT use JTAG on that model.

What you are connecting to is a Serial port. Do a Wiki Search for serial terminal to understand how it works.

My guess is that you just need to erase the nvram and reflash the proper FW.

http://www.dd-wrt.com/wiki/index.php/Netgear_WNR834Bv1

redhawk

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gilsonsjc
DD-WRT Novice


Joined: 12 Mar 2008
Posts: 21

PostPosted: Sat May 29, 2010 23:00    Post subject: Reply with quote
redhawk0, thanks for your response.

The wiki page is not so clear when it comes to what softwares, commands I need to use in order to erase the nvram and reflash the proper FW. Can you please tell me where I can find a step by step on how I can do this?

Fyi, my router shows only the fixed ambar light, it does not ping and I can not tftp at this point.

Thanks
Gilson
gilsonsjc
DD-WRT Novice


Joined: 12 Mar 2008
Posts: 21

PostPosted: Fri Jun 04, 2010 16:41    Post subject: Reply with quote
gilsonsjc wrote:
redhawk0, thanks for your response.

The wiki page is not so clear when it comes to what softwares, commands I need to use in order to erase the nvram and reflash the proper FW. Can you please tell me where I can find a step by step on how I can do this?

Fyi, my router shows only the fixed ambar light, it does not ping and I can not tftp at this point.

Thanks
Gilson


can someone please help me out here? Thanks
Peabody
DD-WRT Guru


Joined: 28 Dec 2009
Posts: 1518

PostPosted: Fri Jun 04, 2010 16:47    Post subject: Reply with quote
Use putty or hyperterminal program. See if you get any output on the screen when you plug in the router.

See the link at the end of number 6 of the peacock announcement.

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gilsonsjc
DD-WRT Novice


Joined: 12 Mar 2008
Posts: 21

PostPosted: Fri Jun 04, 2010 17:12    Post subject: Reply with quote
Peabody wrote:
Use putty or hyperterminal program. See if you get any output on the screen when you plug in the router.

See the link at the end of number 6 of the peacock announcement.


Thanks for your response Peabody.

I have on question: I've tried putty to connect to the router but when I click on open nothing happens. I read here in this post http://www.dd-wrt.com/phpBB2/viewtopic.php?t=56739&postdays=0&postorder=asc&start=30 that the RX and TX need to be crossed out? I have the following

Router VCC to devide vcc
Router GND to device GNC
Router TX to device TX
Router RX to device RX

There is a picture on my previous reply. Please let me know if they need to be inverted or if the connections I did are supposed to work they way they currently are.

Thanks
redhawk0
DD-WRT Guru


Joined: 04 Jan 2007
Posts: 11563
Location: Wherever the wind blows- North America

PostPosted: Fri Jun 04, 2010 17:18    Post subject: Reply with quote
yeah...cross your Rx and Tx....they are referenced from the unit they are on...so the Transmit of one needs to go to Receive of the other...and visa-versa.

redhawk

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gilsonsjc
DD-WRT Novice


Joined: 12 Mar 2008
Posts: 21

PostPosted: Fri Jun 04, 2010 17:55    Post subject: Reply with quote
redhawk0 wrote:
yeah...cross your Rx and Tx....they are referenced from the unit they are on...so the Transmit of one needs to go to Receive of the other...and visa-versa.

redhawk


Ok, I have inverted the TX and RX, connected the devide using a serial to USB adapter. The serial to usb adapter is set to 115200,8,N,1,N using COM5. When I put these settings on PUTTY and click on open nothing happens.

What am I doing wrong?:
Peabody
DD-WRT Guru


Joined: 28 Dec 2009
Posts: 1518

PostPosted: Fri Jun 04, 2010 18:35    Post subject: Reply with quote
If your CFE is corrupt, serial will not work. You would need jtag to fix that and if the router doesn't have a jtag port, you won't be able to fix it.

Try using serial on a working router to check your connections and settings.

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redhawk0
DD-WRT Guru


Joined: 04 Jan 2007
Posts: 11563
Location: Wherever the wind blows- North America

PostPosted: Fri Jun 04, 2010 19:08    Post subject: Reply with quote
I agree with Peabody. I have a Dead 834bv1 also...serial won't work cause the CFE is corrupt.

There is no way to fix it once this occurs....short of removing the flash chip/reprogramming in another unit/replacing the flash chip....its just not worth it for a 834bv1....spend the $80 and get a new router.

redhawk

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crzyruski
DD-WRT Novice


Joined: 07 Sep 2010
Posts: 10

PostPosted: Fri Oct 08, 2010 10:23    Post subject: Reply with quote
Sorry to BUMP.

in my defense: this is the most relevant thread to detail my progress with the WRN834Bv1 serial connection.


ATTEMPT #1 - based on Reviving a failed flash of DD-WRT on a Linksys WRT610n V2.0 – Gaining Console Access

  • I have a functional WNR834Bv1 running DD-WRT v24-sp2 (08/07/10) mini.
  • I also have a bricked WRT610Nv2 (I believe it is fix-able).

  1. I used a volt meter to test both console header - OK
  2. I wired the 160′s WAN port to the console on the 834B - OK
  3. I installed picocom through terminal shell - OK
  4. I fired up “picocom /dev/tts/0″ - it just sits at “Terminal Ready”

[*]I fired up multiple picocom sessions via multiple shell instances (hoping for some data) - nothing.

I have tried to switch the RX and TX lines - no luck...
Note: I power cycled the router for each test.

I think it doesn’t work or I wired it wrong...

ATTEMPT #2 - PC > WNR834B (it gets tricky)


  1. I confirmed the output levels of cable, cable + level shifter, and level from the router's console - OK
  2. Wired up the cable to the converter (based on the datasheet of each) - OK
  3. Wired up the router to the converter + cable - OK
  4. Configured PuTTY as described above - OK
  5. Launched PuTTY in Serial mode - the cursor just sits there...


I have tried to switch the RX and TX lines - no luck...
Note: I power cycled the router for each test.

Of course my next attempt will be to try to get CFE access on the bricked 160Nv2. If it works, then my WNR834Bv1 can be blamed for all this head scratching. If it still doesn't work, then the results are inconclusive Sad there are plenty points of failure.

It seems few have had luck gaining console access to this router... all advice appreciated!

-CR
redhawk0
DD-WRT Guru


Joined: 04 Jan 2007
Posts: 11563
Location: Wherever the wind blows- North America

PostPosted: Fri Oct 08, 2010 14:44    Post subject: Reply with quote
Here is my putty config for Serial terminal.

Double check your settings.

redhawk



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crzyruski
DD-WRT Novice


Joined: 07 Sep 2010
Posts: 10

PostPosted: Sat Oct 09, 2010 9:24    Post subject: Reply with quote
Thank you redhawk0!
but no dice.
I will try with 610Nv2 later this weekend.

BTW, mine is COM4 (I'm sure this is not critical)
Also, I'm running Win 7 x64
bilbotorbins
DD-WRT Novice


Joined: 11 Feb 2011
Posts: 1

PostPosted: Fri Feb 11, 2011 20:25    Post subject: Reply with quote
Excuse me because I'll hijack this thread. I was given a bricked router WNR834 V1. I connected a serial console and powered up the router. Here is the output:

Decompressing..........done
CFE,restore_defaults=üDecompressing..........done
CFE,restore_defaults=0


CFE version 1.0.37 for BCM947XX (32bit,SP,LE)
Build Date: Îå 4ÔÂ 7 16:53:07 CST 2006 (root@localhost.localdomain)
Copyright (C) 2000,2001,2002,2003 Broadcom Corporation.

Initializing Arena
Initializing Devices.
Boot partition size = 131072(0x20000)
et0: Broadcom BCM47xx 10/100 Mbps Ethernet Controller 3.90.23.0
rndis0: Broadcom USB RNDIS Network Adapter (P-t-P)
et1: Broadcom BCM47xx 10/100 Mbps Ethernet Controller 3.90.23.0
CPU type 0x29006: 264MHz
Total memory: 16384 KBytes

Total memory used by CFE: 0x80300000 - 0x807D3780 (5060480)
Initialized Data: 0x80333F10 - 0x80336DD0 (11968)
BSS Area: 0x80336DD0 - 0x8076D780 (4417968)
Local Heap: 0x8076D780 - 0x807D1780 (409600)
Stack Area: 0x807D1780 - 0x807D3780 (8192)
Text (code) segment: 0x80300000 - 0x80333F10 (212752)
Boot area (physical): 0x007D4000 - 0x00814000
Relocation Factor: I:00000000 - D:00000000

mac address in flash is:00:18:4d:07:bc:bc
have eRcOmM
before pushbutton
et0macaddr=00:C0:02:63:00:08
run kernel
nvram header:
46:4c:53:48:34:02:00:00:a9:01:
0b:00:62:00:00:00:07:03:01:00:
Device eth0: hwaddr 00-C0-02-63-00-08, ipaddr 192.168.1.1, mask 255.255.255.0
gateway not set, nameserver not set
Invalid boot block on disk
Reading :: Failed.: Timeout occured
Reading :: Failed.: Timeout occured
Reading :: Failed.: Timeout occured
Reading :: Failed.: Timeout occured
Reading :: Failed.: Timeout occured
Reading :: Failed.: Timeout occured
Reading :: Failed.: Timeout occured
Reading :: Failed.: Timeout occured
Reading :: Failed.: Timeout occured
Reading :: Failed.: Timeout occured
Reading :: Failed.: Timeout occured
Reading :: Failed.: Timeout occured
Reading :: Failed.: Timeout occured
Reading :: Failed.: Timeout occured
Reading :: Failed.: Timeout occured
Reading :: Failed.: Timeout occured
Reading :: Failed.: Timeout occured
Reading :: Failed.: Timeout occured
Reading :: Failed.: Interrupted
CFE> nvram erase
*** command status = 0
CFE>

When I turn on the router only the amber light is lit continuously. I could ping the router and the TTL is 100, but when I try to put the firmware from Netgear with tftp I receive message "succes" and nothing happens.
I would appreciate any ideas.
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