From DD-WRT Wiki
 Flashing WRT54G-TM
NOTE: During configuration or flashing a device, the only things that should be hooked to the device is the computer and power.
 How to flash the Linksys WRT54G-TM T-Mobile Edition by Luniz2k1
Please note that this guide is ONLY for the WRT54G-TM router and nothing else. Do NOT attempt to use this method on any other device, as it is written ONLY for the WRT54G-TM router. (Linksys WRT54G-TM and WRT54G-RG are identical in terms of hardware, but differ in terms of firmware, so you MUST USE THE CORRECT files. The WRT54G-TM was a t-mobile router put out by Linksys, and the WRT54G-RG was a Rogers router put out by rogers in Canada. )
In order to flash this router you need to do the following steps:
- Download the DD-WRT firmware (v24-SP2 build 12548 OR NEWER is suggested)
NOTE: Check the Peacock thread for recommended build numbers if unsure.
- Download the TFTP utility
- Download Tornado's CFE_Updater-WRT54G-TM.bin
- Turn OFF/Disable any AV/Firewall on your pc.
- Make sure your pc is wired to a LAN port on the router when flashing.
Note to new users: Do your research and find out what the latest build is and use it from the start, unless there are issues with the latest build preventing the WRT54G-TM from operating properly, then go to a previous build.
1. The default LAN IP Address of the Linksys WRT54G-TM is 192.168.0.1. You will need to set a Static IP Address on your computer for this procedure. If you are on Windows I suggest that you reset the router to it's defaults and set 2 LAN IP Address on your network controller to speed up the process, otherwise once you upload the CFE_Updater-WRT54G-TM.bin you will need to change your LAN IP Address from 192.168.0.2 to 192.168.1.2 to be able to TFTP DD-WRT onto the router.
On Windows XP, Control Panel/Network Connections/right-click on Local Area Connection icon and select Properties. On Windows Vista, Control Panel/Network and Sharing Center.
Go into the properties of the Local Area Connection/Internet Protocol TCP/IP and set the static IP address.
IP Address: 192.168.0.2 Subnet Mask: 255.255.255.0 Default Gateway: 192.168.0.1
Click the Advanced button in the TCP/IP setup window and in the IP Address section click the ADD button to add the following 2nd IP Address to the adapter:
IP Address: 192.168.1.2 Subnet Mask: 255.255.255.0
Then click OK on each screen. Your network interface card (NIC) now has 2 LAN IP Address statically set on it, 192.168.0.2 and 192.168.1.2. This will allow your PC to communicate with the router before and after replacing the CFE on it. It will also allow you to be able to tell when the router is ready for a TFTP upload.
2. Open a command prompt window and type ping -t 192.168.1.1 and hit enter. Leave this window open.
3. Log into the WRT54G-TM's web interface @ http://192.168.0.1 (assuming that the router has been reset to defaults) and go to the Administration Tab - Firmware Upgrade. Upload the CFE_Updater-WRT54G-TM.bin to the router.
!!!ATTENTION!!! You MUST wait at least 5 minutes after clicking the Upgrade button to allow the CFE_Updater to replace the stock CFE on the router and for it to erase the rest of the flash, otherwise you will brick your router.
A few seconds after clicking the Upgrade button the Linksys web interface will report that the upload has been successful and the power light will begin flashing on the router. Do NOT assume that the CFE replacement/flash erasing/reboot process has finished as the power light will continue to flash after it has rebooted. So there is no way to tell when it is ready for you to TFTP the DD-WRT firmware to it except when you begin to see the ping respond.
So once it is finished replacing the stock CFE and erasing the rest of the flash, the router will reboot. When the router is ready for the TFTP upload of the DD-WRT firmware, you will see the ping -t 192.168.1.1 begin to respond in the command prompt window that you opened before.
4. Start up the TFTP utility and set the following:
Server: 192.168.1.1 Password: <leave blank> File: <path to dd-wrt.v24-12548_NEWD_mega.bin> (or whichever build you wish to use)
Now click the Upgrade button. Once the firmware is sent to the router, it will reboot. The power light will change from flashing to solid when it is ready to be configured @ http://192.168.1.1
If you do not see a progress bar as the tftp utility transmits the file, you may need to power cycle your router. Wait until the tftp utility has finished its attempts, then power cycle (possibly waiting a few seconds) and wait until you can ping 192.168.1.1 before clicking Upgrade again.
A few notes:
- Tornado has made it so that the router will retain it's MAC Address that is on the label on the bottom of the router with the new CFE replacement.
- Tornado is in the process of making a revert bin for those who may choose to revert back to the stock Linksys firmware (god only know why)
Many thanks goes out to Tornado, Eko, and Brainslayer for their work on this!!! Cool
No more will you need to void your warranty by opening the WRT54G-TM to JTAG DD-WRT onto it, or spending $70+ USD for a WRT54G-TM pre-loaded with DD-WRT from eBay
 How to revert the Linksys WRT54G-TM T-Mobile Edition
Note: The default IP of the router will change from the default DD-WRT IP of 192.168.1.1, to the Linksys default IP of 192.168.0.1 midway through the process.
You will have to change the static IP of your rig accordingly.
Read and understand these procedures before attempting the revert process.
This procedure assumes you have the fundamental skills to access your router, set a static IP on your rig, and use the tftp utility found here on the forum. As with anything else in regards to cutting edge technology, you the user assume all risks.
If for some reason your mac’s (mac addresses) are not correct (per the sticker on your box), this process will let you change them. See :”To change the mac addresses of your router:” below.
If you mac’s are correct, you have to do nothing except run the revert utility.
No Mac Change:
1). Reset your box (router) to factory settings via the GUI.
2). Set a static IP on your rig of 192.168.1.110, subnet mask of 255.255.255.0, Default gateway of 192.168.1.1.
3). Access your router via the GUI. Depending of the version of DD-WRT that is on the box, you may be asked the change the user name and password.
4). Set the user name to “root” (no quotes)
5). Set the password to “admin” (no quotes)
6). Click “Change Password”
7).From the Administration tab, choose “Firmware Upgrade”.
8).Browse to the location of the TM-Revert.bin file and select it. Click the “Upgrade” button at the bottom of the page.
The file is a program that is loaded and executed by the router. This is not just flashing data. This will take some time to complete. Leave your router alone for at least five minutes after clicking the upgrade button.
The status of the led’s will be after running the revert: Power light flashing, wlan light off, only the lan light your rig is plugged into should be lit.
9). After two minutes, you need to change the static IP of your rig as well as the default gateway to the default Linksys IP. Change the IP of your rig to 192.168.0.110, subnet mask of 255.255.255.0, gateway 192.168.0.1
10). After 5 full minutes, it is now safe to tftp the stock Linksys firmware. If you are so inclined, you can verify by pinging 192.168.0.1. You should get a response and TTL=100 should be displayed.
11). Power cycling the device is not necessary. The revert has been tested both ways. One way, tftp the stock Linksys firmware without power cycling after waiting the full five minutes.
The other way, after waiting the full five minutes, power cycle the device, then tftp the stock Linksys firmware.
After the successful tftp of the stock firmware, the router will boot by itself. Leave the router alone after you receive a success message from the tftp utility.
You will know when the reboot is complete as the power led will quit blinking and turn solid, and the wlan led will illuminate. Once complete, access the devices GUI at 192.168.0.1 and configure to your liking.
Congratulations. You are done.
 To change the mac addresses of your router:
If for some reason, your mac addresses are not correct per the sticker on your router, or if you would just prefer to change them…
First follow steps 1 through 6 above. Then:
1a). From the Administration, Commands tab, enter the following in the commands box:
2a). nvram set et0macaddr=your mac here (format = XX:XX:XX:XX:XX:XX)
Example: nvram set et0macaddr=00:10:20:30:40:A1
3a). Click “Run Commands”
4a). Enter the following command in the Commands Box:
5a). nvram commit
6a). Click “Run Commands”
Note: the nvram set et0macaddr and the nvram commit can be combined in the commands box. Example:
nvram set et0macaddr=xx:xx:xx:xx:xx nvram commit
After the two commands above are entered in the commands box, you can then click “Run Commands”
7a). From the Administration, Management tab, click “Reboot Router”
After the router reboots, verify the mac addresses are the ones you set via the status page.
At this point, you can follow the revert instructions above. The routine will complete and your permanent mac addresses will be as you set. You are back to stock Linksys firmware.
 Hardware Mods
If you do the above mods, you may want to look into upgrading your power supply.