Jailbreak 4.2.1 iPhone 4 3GS iPod Touch 4G 3G iPad with Limera1n Untethered Jailbreak ?

After Apple has released iOS 4.2.1, iPhone dev-team has updated Redsn0w to jailbreak all iOS devices on iOS 4.2.1, For those of you who don�t know, the new upgrades which has been done to Redsn0w in beta 4,5 and 6, based on Geohot�s Limera1n bootrom exploit which has already pwned all current iOS devices for life.
but unfortunately redsn0w was tethered for (iPhone 4, 3GS (new bootrom), iPod touch 4G 3G, 2G (MC Model) and iPad). Now, Limera1n will be upgraded to be untethered jailbreak for these devices or not?

Theoretically, Limera1n can be modified to be untethered jailbreak for all iOS devices for life time, as Geohot has an iboot-level untethered exploit but it has not been announced yet, till now there's no estimate to arrival for the limera1n unntethered jailbreak for iOS 4.2.1, but expect to see it soon.