We told you yesterday that RedSn0w was already able to jailbreak iOS 5.0.1 beta, but it wasn’t completely flawless, as you had to point RedSn0w to the iOS 5 IPSW. MuscleNerd just confirmed that he has added iOS 5.0.1 beta keys to RedSn0w 0.9.9b8, making the jailbreak process this much easier…
If you are an unlocker who runs an iPhone 3GS or iPhone 4 and want to update while preserving your baseband, the Mac version of RedSn0w 0.9.9b8 will allow you to do just that, but note that UltraSn0w may or may not work on iOS 5.0.1 beta as it hasn’t been updated yet, and probably won’t until 5.0.1 goes public.
redsn0w version 0.9.9b8 will natively recognize the 5.0.1 beta that Apple let developers start testing this week (so you don’t have to play the “point at 5.0 IPSW” trick). Because the IPSW isn’t public, you’ll still need to provide it once to redsn0w (at which point it will cache all the important pieces so you don’t need to select it again).
For those 3GS and i4 users who preserve their baseband, the Mac version can also produce the NO_BB_* custom IPSWs for 5.0.1. (But please note that ultrasn0w doesn’t get updated for betas like this.)