I recently purchased a Linksys WRT54G-TM (the T-Mobile one) off ebay for $40. My intention was to flash the firmware to DD-WRT or Tomato. I need to put a couple of computer workstations out on our factory floor, but I don't want to have to run ethernet cable out to them. Instead, I thought I'd try to form a wireless bridge with our existing Linksys wireless router that's in the office.Some background information:
Different versions of Linksys WRT54G wireless routers have different processors and amounts of memory, so you have to choose carefully before purchasing one. You may need to have the seller look on the bottom of the unit for the serial and/or version number. From what I've heard, once Linksys found out that people were flashing custom firmware on to their routers, they started reducing the memory in the units and put in some kind of CFE ("Common Firmware Environment") that could detect if the factory firmware was overwritten and automatically restore it.
I wanted to flash the Tomato firmware onto my unit but apparently Tomato doesn't have any method of flashing the CFE. So first I had to follow these instructions to flash the CFE and load DD-WRT. These instructions worked like a charm for me, and then it was quite simple to update the firmware to Tomato from DD-WRT.
Once I had Tomato loaded, I switched it to "Wireless Ethernet Bridge" mode and then I entered the same SSID and security key from my existing wireless router and voila! all I have to do is plug the power cable in and I have instant wireless access to our network anywhere within the range of my existing wireless router, as though I were connected with an ethernet cable!
The only thing I'm worried about now is the unit overheating when it gets hot out on the plant floor in the summertime. I'm thinking about underclocking the unit to make it run cooler, because it runs a little warm right now at the default 200MHz. The telnet login username is "root", and the password is what you set it to be in the web-admin interface.