Category: WNR3500L v2

Netgear WNR3500L v2 unbrick

I was playing with this router till I bricked it. Following is the recovery procedure it worked for me, tested on Xubuntu 12.04.

Firstly set your lan interface to obtain a fixed IP in the subnet 192.168.1.x subnet, such as 192.168.1.10, netmask 255.255.255.0 as usual.

 

Firmware download

Visit www.myopenrouter.com to have a look to the best firmwares available, this time I decided for the Tomato 093-AIO (All In One), all versions are here.

Download and extract the firmware with chk extension in a temporary directory.

 

The terminal

Built a TTL cable to use the terminal through the internal connector JP1 which has this pin out:

[1] VCC

[2] RX

[3] NC

[4] NC

[5] TX

[6] GND

 

Open a terminal emulator such as putty and configure the serial for a speed or 115200 baud and leave the other options set to default (8N1). On Xubuntu you can install it with a simple

sudo apt-get install putty

 

Enter the bootloader

Power cycle the router, press immediately and continuously  CTRL+C to interrupt the bootloader and get the CFE prompt (this assumes you have the TTL serial adapter connected and ready to go)

 

Decompressing...done

CFE for WNR3500Lv2 version: v1.0.9
Build Date: Fri May  6 11:54:17 CST 2011
Init Arena
Init Devs.
Boot partition size = 262144(0x40000)
NFLASH Boot partition size = 524288(0x80000)
et0: Broadcom BCM47XX 10/100/1000 Mbps Ethernet Controller 5.60.136
CPU type 0x19749: 480MHz
Tot mem: 131072 KBytes

Device eth0:  hwaddr 74-44-01-33-BD-C2, ipaddr 192.168.1.1, mask 255.255.255.0
        gateway not set, nameserver not set
Startup canceled
CFE> ^C
CFE>

 

Nvram erase

Clear the nvram, missing this operation is often the cause of bricked routers

CFE> nvram erase
*** command status = 0
CFE> nvram commit
*** command status = 0

 

TFTP server

Start the TFTP server

CFE> tftpd
Start TFTP server
Reading ::

 

Firmware upload and upgrade

Move to the directory where the firmware was previously extracted and upload it to the router using a TFTP client

tftp -m binary 192.168.1.1 -c put tomato-Netgear-3500Lv2-K26USB-1.28.RT-N5x--093-AIO.chk

The procedure is quite silent, so don’t touch anything and after some minutes the router will reboot successfully

 

Open your browser to http://192.168.1.1 and enjoy your new firmware.

 

References

http://tomatousb.org/

http://www.myopenrouter.com


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