The original development was done on Linksys WRT54G hardware versions 1 through 4. Starting with hardware version 5, the firmware Flash and working RAM memory were reduced and the factory operating system was changed to VXworks. Version 5+ WRT54G and GS units don't have enough memory to run HSMM-MESH™. A repackaged version of a WRT54G is separately marketed as WRT54GL (for Linux) and is specifically advertised as supporting Linux.

Versions 1 through 4 of the WRT54GS are also supported.

The supported versions of the router all have a minimum of 4 Mb of Flash memory and 16 Mb of RAM.

Linksys Devices

There are some great charts for spotting WRT54Gxx versions on Wikipedia.org. Hardware versions are on the device label on the bottom but the font is very small and difficult to read. Keep in mind that the WRT54G v 1.0 uses only regulated 5.0v power. Higher voltage will let the smoke out. V 1.0 units are easy to spot since they have 3 status LEDs for each LAN jack and all others have one.The easiest way to determine hardware versions on Linksys devices is to read the serial number. The first few letters of the serial number decode the actual hardware version using the chart below. These serial numbers are also printed on the outside of new hardware boxes near the UPC barcode and can be read without buying the product or opening the box.

Hardware guide to print as you look over used devices.