LINKSYS WIRELESS GWRT54G ROUTER

As of January 2006, most third-party firmware is no longer compatible with version 5 of both the WRT54G and the WRT54GS. The amount of flash memory in the version 5 devices has been reduced to 2 MB, too small for current Linux-based third-party firmware. (See table above for information on identifying the version based on the serial number printed on the bottom of the unit, and on the outside of the shrink-wrapped retail box.)
Some users have succeeded in flashing and running a stripped down but fully functional version of DD-WRT called 'micro' on a version 5 WRT54G.^[20][21] An easier method not requiring any disassembly of the device has since been devised for flashing v5-v8 to DD-WRT.^[22][23]
To support third-party firmware, Linksys has re-released the WRT54G v4, under the new model name WRT54GL (the 'L' in this name allegedly stands for 'Linux'). It is also possible to replace the 2MB flash chip in the WRT54G with a 4MB flash chip. The Macronix International 29LV320BTC-90 is a suitable part although others may work as well. The user must first install a JTAG header and use a JTAG cable to backup the firmware,then replace the chip and restore the firmware with the JTAG cable. After testing for proper functionality of the modified unit,3rd party firmware can be flashed using the JTAG cable and a suitable image file.