Apple has updated Apple TV 2G to iOS 4.2.2 (iOS 4.3 build 8F305). This release contains various bug fixes and improvements over the last release. Earlier, Apple TV 4.2.1 was released which fixed video flickering issue along with other bugs fixes.
The official changelog as follows:
Addresses an issue in which audio is not output when playing some video content.
Addresses an issue in which video is not displayed when playing some content.
Audio output setting
Adds an audio output setting for switching to 16-bit audio for compatibility with some TVs and AV receivers.
Live FF/RW improvements
Improves the performance of fast-forwarding and rewinding live events.
Addresses an issue in which the description information is not displayed for some movies.
YouTube video order
Addresses an issue in which YouTube subscription videos were not ordered by date.
Procedure to Update Apple TV 2G to iOS 4.2.2
To update Apple TV to iOS 4.2.2 go to Settings >> General on your Apple TV and then click on Update Software.You can then download and install the software.
Jailbreakers should avoid updating to Apple TV 2G 4.2.2.
Download Apple TV 4.2.2 (8F305).