There has been a lot of confusion lately as to what's going on with the end of Linux support on the WRT54G and WRT54GS line of routers. Hopefully I'll be able to describe what's going on, what's changing, what's coming, and what you can do about it.
Q:Is this it true the WRT54G and WRT54GS no longer run Linux?
Partially, it is true that the latest hardware revision (v5.0) of the WRT54G no longer runs the open source operating system Linux. The WRT54G v5 now runs VxWorks, a closed operating system by Wind River, designed to provide real time operating systems that provide highly optimized performance at a reasonable cost for embedded devices, appliances, and other RT demand applications. The decision by Linksys to moved from linux to VxWorks was apparently influenced by these factors. I've been told that despite the somewhat neutered hardware specs compared with previous versions, the v5 provides higher throughput and better performance at least on the wired LAN and routing side. According the Linksys, "The move to VxWorks allow us to run a more efficient code, which results in better routing performance." This move to the VxWorks based firmware has also brought firmware versioning back to 1.XX for the v5 hardware only (Currently 1.00.2).
Full Whatever-it-is .