I have a ATV G2 Black. I used Seas0npass 0.6.9 and installed XBMC using aTV Flash (black). I was a happy guy as it worked wonderfull!
I then made the mistake of anwering the "do you want to upgade" with "yes" when i wanted to reboot my aTV.
The upgrade to overall went well but afterwards no wifi and XBMC not playing MKV.
I decided to go back to 4.2 (Seas0n pass 0.6.9). This only worked after a factory settings restore in iTunes.
After removing the ipsw files in my (Mac) home directory and the Tether folder in my Documentsfolder i was able to restore to 4.2.1
This fixed the MKV playing issue in XMBC but still no Wifi. I do have ethernet over the cable but i cannot see any Wifi SSID's.
I know the Wifi works because when booting after i restord to factory settings Wifi worked fine.
Any suggestions anyone?