MuscleNerd, who happens to be one of the core members of iPhone Dev-Team has just confirmed that Stefan Esser's (@i0n1c) untethered exploit also covers Apple TV 2G. This means that along with untethered iOS 4.3.x jailbreak for iPhone 4/3GS, iPod Touch 4G/3G and iPad, we will be having untethered iOS 4.2.1 (iOS 4.3) jailbreak for Apple TV 2G as well.
untether from @i0n1c also covers ATV2. Thanks to @saurik & @nitoTV for getting rest of ATV2 JB ready http://is.gd/0leGcR
MuscleNerd also confirmed that iOS 4.3.1/4.3 untethered jailbreak will be coming in the form of PwnageTool and Redsn0w. For those who don't know, PwnageTool lets you to preserve your current baseband while Redsn0w involves baseband upgradation which is suitable for those who do not rely on an unlocked iPhone.
For those who don't know, all iDevices except iPad 2 has been already jailbroken on iOS 4.3 (Windows | Mac OS X) and iOS 4.3.1 (Windows | Mac OS X) by using Sn0wbreeze and PwnageTool bundles. As all iOS 4.3 and iOS 4.3.1 current jailbreaks (except iPhone 3GS (Old Bootrom) users) are tethered, so you must use iBooty or TetheredBoot Utility to boot your iDevice into tethered jailbroken state.
As kernel exploit to jailbreak iOS 4.3 on iPad 2 has been fixed in iOS 4.3.1, so the upcoming untethered jailbreak wont be covering iPad 2 users. Chronic-Dev Team and Comex is already working on the jailbreak on iPad 2.