Apple has quietly pushed out an update
for its second-generation Apple TV running iOS. The Apple TV 4.2.1 update addresses a couple of incredibly annoying bugs, which we've personally suffered from, including a flickering picture and a lack of audio when switching through sources on some TVs and AV receivers. The update should also cure the problem of the Apple TV sleeping with the fishes and failing to wake up when commanded by the remote. Apple also lists various 'stability and performance fixes' for the Apple TV, so with a bit of luck if you've got any outstanding issues from the previous update, they should be gone with 4.2.1.
The Apple TV 4.2.1 update can be downloaded either over-the-air on the Apple TV itself, or restored via iTunes.