It is true that the IOS is available on Apple TV 4.2.2 2G, but it is not official yet, since Apple has not officially updated the download page for IOS 4.2.2. But the good news is that the Apple TV, 2G users can now upgrade to 4.2.2 IOS. And we are down, when I wrote it.
This is the first update of the Apple TV since last March, namely the IOS 4.2.1 was released. This new update for Apple TV brings some improvements in audio and video experience, and some errors are fixed.
Just connect your 2G Apple TV using a USB cable to your computer or Mac iTunes and click the Update button and iTunes will update the Apple TV 2G quickly.
NOTE: Jailbreak jailbroken 2G with the free Apple TV should
avoid 4.2.2 update IOS then maybe your loss Jailbreak for this update.