Same goes for me, I upgraded firmware, and now I can't connect to my wifi. Tried to change SSID, run setup and configure everything but wifi is not available on any of my devices.
I have select keep my old settings when doing firmware upgrade. After firmware upgrade my mac was able to connect to wifi with old settings, but my girlfriends asus wasn't, so I started renaming wifi name, changing passwords etc etc.. Maybe I should have gone with reset to factory defaults... I was stressed...
Edit: SOLVED
Via LAN cable connected to my router 192.168.11.1 did an online firmware upgrade (just in case, and to test how this cool function works) with selection of reseting all my previous router settings (factory defaults), later on configured wifi names and passwords to my liking. Yahooo!