Determine which model of WRT54G you have including the version number. This is done flipping the router over and looking at the attached label.
The next step is to go to www.linksys.com and then select support.
Enter in the Model number of your node
Select the downloads tab
Enter the version number of your hardware
Click on the download link
You will need to scroll to the bottom of the screen and accept the License Agreement
Save the firmware file to your computer
What we are going to do now is a TFTP upload of the firmware you just downloaded. A more complete discussion of this can be found at http://www.broadband-hamnet.org/documentation/68-firmware-installation-instructions.html. I have found that if you are using a windows computer it is best to connect the router to a Ethernet switch and the switch to the computer.
Also this is much easier to do on a linux computer. There is a script in the firmware installations on the BBHN website (link in the above paragraph) that keeps trying to load the file until it is successful. You just keep power cycling the node until the script is successful.
Set your computer to have a static IP in the 192.168.1.xxx range. Do not use .1.
Open and command window and change to the directory where you stored the firmware.
When the BBHN firmware was loaded on router, a setting was made that allows for an approximately 1 second window as the node is first booted up for the node to accept a tftp upload of new firmware. This is a failsafe that may allow you to recover your node if you brick it or lose the password. The way we use this to upload the firmware is to enter the tftp command into command window, unplug the router, reconnect power to the router and hit enter to execute the command.
tftp -i 192.168.1.1 put <firmware_file_name.bin>
As you can see from the picture above, it can take a few tries to hit that window.
At this point the node reboots. Go in and change your computer back to “uptain an IP address automatically.”
At this point you should be able to unplug your Ethernet cable from your computer and then reconnect it to get a new IP from the router. In a web browser, connect to the router using 192.168.1.1. The default user and password is “admin”.
And you can always return the node back to a BBHN node by installing the BBHN firmware using the normal instructions.