Apple has already released iOS 4.2.1 for Apple TV 2G. The release fixes minor bugs and display flickering. It also fixes problem arising when waking from sleep and the audio output. Now Firecore has released an updated version of Seas0npass which will tethered Jailbreak Apple TV 4.2.1 (iOS 4.3).
If you are unaware of this, Seas0npass is a jailbreak tool developer specifically for the Apple TV. It offers an easy to use and a beautiful interface which jailbreak tools normally do not offer.
The Guide to Jailbreak Apple TV 2G 4.2.1 is same as earlier guide of Seas0npass which we posted, except for the updated version of Seas0npass which will jailbreak 4.2.1.
Download Seas0nPass For Apple TV 2G 4.2.1