From the Taking It Back dept.:
As predicted, the open source community has come up with a way to convert VxWorks-based LinkSys wireless WRT54G routers to Linux. The process does not require hardware hacking, and installs a recent version of "DD-WRT micro."

A version of Linux that supports the VxWorks-based "series 5" WRT54G has been available since April, when the DD-WRT project created its "micro" edition, with a 1.7MB footprint. However, the firmware could only be installed on routers modified to expose their JTAG ports.

Now, Jeremy Collake, aka "db90h," appears to have created a "VxWorks Killer" flash image that overwrites the VxWorks bootloader on series 5 WRT54G routers with normal Broadcom CFE firmware. This then enables the device to be put into maintenance mode at startup, after which Linux firmware can be installed easily.

linuxdevices.com | Instructions & Project