Moments ago Apple just released Update for Apple TV 2G. The new firmware is iOS 4.2.2 and iOS 4.3. The firmware will have some bugs fixed and some new updates.
Moments after the release @MuscleNerd said to stay away from the Update.
Apple just pushed out a lone AppleTV2G update…stay away from that if you’re currently untethered on ATV2G
You can Download the Update from here Manually.