http://polarcloud.com/
How do I find my Linksys WRT54G/WRT54GS/WRT54GL's version?[toc, link]
Look at the bottom side of the router to check for the version number, or compare the first 4 characters of the serial number with the following list:
CDF0/CDF1 = WRT54G v1.0
CDF2/CDF3 = WRT54G v1.1
CDF5 = WRT54G v2.0
CDF7 = WRT54G v2.2
CDF8 = WRT54G v3.0
CDF9 = WRT54G v3.1
CDFA = WRT54G v4.0
CGN0/CGN1 = WRT54GS v1.0
CGN2 = WRT54GS v1.1
CGN3 = WRT54GS v2.0
CGN4 = WRT54GS v2.1
CGN5 = WRT54GS v3.0
CGN6 = WRT54GS v4.0
CL7A = WRT54GL v1.0
CL7B = WRT54GL v1.1
CL7C = WRT54GL v1.1
CF7C = WRT54GL v1.1
If it's not listed above, and it's not a WRT54GL, it's not supported.
awesome firmware