Stefan Esser a.k.a. i0n1c has informed us that he has given his beta untethered exploit to the iPhone-Dev Team. The untether work on iOS 4.3 and 4.3.1. Although the iPad 2 is vulnerable to the exploit, there is currently no way to inject it. In the other devices, it can be injected using the limera1n bootrom exploit.
We will likely see this untether appear in a redsn0w update, but there is no ETA for the release.
The iphone-dev-team is already beta-testing the untether. So it is up to them to give you your tool of choice.
-i0n1c
