Posted: Sat Apr 17, 2010 0:58 Post subject: How to unbrick WNR834B v1 (JTAG HELP)
Greetings from Brazil!
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?)
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
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
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.
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.
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. _________________ I fix "shortcuts". If you don't have time to read thoroughly, I don't have time to re-type what you missed.
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.
Joined: 04 Jan 2007 Posts: 11563 Location: Wherever the wind blows- North America
Posted: Fri Jun 04, 2010 17:18 Post subject:
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 _________________ The only stupid question....is the unasked one.
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.
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. _________________ I fix "shortcuts". If you don't have time to read thoroughly, I don't have time to re-type what you missed.
Joined: 04 Jan 2007 Posts: 11563 Location: Wherever the wind blows- North America
Posted: Fri Jun 04, 2010 19:08 Post subject:
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 _________________ The only stupid question....is the unasked one.
I confirmed the output levels of cable, cable + level shifter, and level from the router's console - OK
Wired up the cable to the converter (based on the datasheet of each) - OK
Wired up the router to the converter + cable - OK
Configured PuTTY as described above - OK
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 there are plenty points of failure.
It seems few have had luck gaining console access to this router... all advice appreciated!
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:
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.