In the Linksys support page there are no more firmware files for this device. Browsing internet i found the 3.08.06 release . It works on the 3.1 hardware version only.
Version 3.08.06, Apr 06, 2010
– Fix: MAC address may reset to default after changing settings.
– Fix: While in client mode, device will re-connect to AP after connection drops.
– Fix: WDS does not work when wireless security is enabled.
– Fix: Correct wireless channel range in user interface.
– Fix: Debug page security vulnerability.