Apple TV 2If you own an Apple TV 2 can be, so you should definitely currently remain on iOS 5.0.2. This software version is signed for the Apple TV still and is untethered jailbreakbar. The situation is different with the latest software version 5.1 for iOS (iOS 6 adaptation for the Apple TV's). This is currently only jailbreakbar via redsn0w tethered. Furthermore, very few jailbreak tweaks work for iOS 5.1 for the Apple TV.
|Nito TV status jailbreak|
Since iOS 5.1 is such a "senseless" update for the Apple TV 2, hackers are wasting no time to develop an untethered iOS 5.1 jailbreak. If you want to install the latest software update necessarily have to deal with the tethered jailbreak to be satisfied via redsn0w.
Apple TV 3The iOS 5.0.2 untethered jailbreak iOS 5.1 jailbreak and tethered for the Apple TV 2 is made possible by the famous Limera1n bootrom exploit. The Apple TV 3 has, however, a new chipset, which Apple has the Limera1n exploit. For this reason, the Apple TV 3 is currently not jailbreak bar.
According nitoTV this is unfortunately still some time to come. The slimmed iOS firmware for Apple TV's can unfortunately only little "unassailable material" left over, so that user-level exploits are hard to find. But a bootrom exploit is currently not in view.
|Apple TV 3|