Apple has released a minor software update for the Apple TV 2G, the iOS 4.2.1 (4.3.1) update. Few days before, Apple released the iOS 4.3 firmware for the other devices and now an update for the Apple TV 2G. iOS 4.2.1 update has included changes like more performance and stability and have also fixed some issues with the audio, screen (flickering), and the sleep feature.

Download iOS 4.3.1 IPSW for Apple TV 2G

 

The following is the official change log for the iOS 4.2.1 (iOS 4.3.1) update :

TV compatibilityAddresses issues that may cause the screen to flicker or display incorrect color on some older TVs.
Wake from sleepAddresses an issue where Apple TV may not wake up from sleep.
AudioAddresses an issue where audio may not be heard on some TV models after switching from another input.
Stability and performanceApple TV Software Update 4.2.1 includes stability and performance fixes for Apple TV.

 

You could update to it automatically or do it manually using iTunes after downloading the below IPSW.

Download iOS 4.3.1 IPSW for Apple TV 2G from here