A friend was having some trouble with the Netgear wireless router he was given by Virgin Media, which I fixed by replacing the Virgin-supplied firmware with the latest Netgear firmware. Doing this required a bit of digging around, so I thought I'd write a quick guide to sum up the information I found online.

First up, you need the latest firmware from Netgear. My friend has the WGR614v9, for which the latest firmware (at time of writing) can be found at http://kb.netgear.com/app/answers/detail/a_id/3808. Download the firmware from this page and open it up in a hex editor. On Windows I have tried out Geoff Prewett's HexEdit, which seems to do the job, and on Linux I recommend Pixel's hexedit - despite the name, these are not the same program!

In the hex editor, open up the firmware image. You're looking for the board ID that the firmware is intended for, which is in the file near the top and should look something like U12H094T00_NETGEAR. Make a note of it. Once you've got it, it's time to set the router to accept firmware for this board ID. To do so, you'll need to

1. Enable telnet access on the router
2. Telnet into the router
3. Change the router's board ID

You can enable telnet on the router using a program called telnetEnable - see OpenWRT or Remote Exploit for information about it. First, log into your router. The usual way to do this is to open a web browser and go to http://routerlogin.com/. It will ask for a username and password, the default Virgin Media setup is usually virgin for the username and password for the password, it's written on the label on the underside of the router so you can check for yourself if that doesn't work. Go to the "Router Status" page and look up the router's MAC address, which will be of the form 00:11:22:33:44:55:66. Make a note of this too. If you've changed any of the settings you may want to make a note of these too, as they will be lost when you overwrite the firmware.

Download the telnetEnable program from one of the links given above, and then open up a command prompt (on Windows you can do this by pressing the Windows key and 'R' simultaneously and typing cmd into the box that appears). Change directory to the telnetEnable program - you may need to unzip it first - and run it using the following command:
telnetEnable.exe routerlogin.com 00112233445566 Gearguy Geardog
Here 00112233445566 is the router MAC address that you noted down earlier, with any ':' characters removed. You should then be able to log in to the router using the command telnet routerlogin.com. If all is well, you should see something like the following:

Trying 192.168.1.1...
Connected to routerlogin.com.
Escape character is '^]'.

BusyBox v0.61.pre (2008.02.12-10:44+0000) Built-in shell (ash)
Enter 'help' for a list of built-in commands.

#

At the '#' prompt, type the command burnboardid U12H094T00_NETGEAR (where U12H094T00_NETGEAR is the firmware board ID you noted down earlier), and then restart the router with the command reboot.

Once the router has rebooted, you should be able to log in to it again from the web interface at http://routerlogin.com/. Go to the "Router Upgrade" page, select "Browse" and give it the location of the firmware that you downloaded earlier. For some reason if you try to do this in Firefox it gives an "Invalid filename for firmware" error. The upload works in Internet Explorer, I'm not about other browsers as I didn't have any handy to test with. The router should then tell you it is upgrading the firmware. Once it's finished, you'll be prompted to log in again, and since it's now using the Netgear firmware the username is admin and the password is password. You are now done and ready to configure the Netgear firmware to your heart's content.

Final note: Once you start using the new firmware, I recommend changing the password and setting up the wireless to use WPA2-AES as this will make your network more secure.

Source: Most of the information in this post originally came from http://forum1.netgear.com/showthread.php?p=148146. Many thanks to DanielV.