This is the tweet from MuscleNerd posted a minute ago. So it is just minutes to wait for new unlock utility ultrasn0w.
UPDATE 2: new ultrasn0w 1.2 supports the following basebands:
UPDATE 3: Step-by-step Tutorial: How to Jailbreak and Unlock
Finally got ultrasn0w working fully on 4.2.1. Apple inadvertently(!) broke ultrasn0w via aggressive compiler optimization
UPDATE: this is not a reason for update to iOS 4.2.1, wait for utilities.
DevTeam hacker MuscleNerd tweeted that they after releasing redsn0w jailbreak for 4.2 the team can start working on iPhone unlock. Users can expect the unlock for the iPhone 3G and iPhone 3GS this week. The iPhone 4 unlock will take more time and no concrete info is available about that yet.
The ultrasn0w unlock will be released for iOS 4.1 firmware. So is you need unlock, do not update to iOS 4.2.1.
MuscleNerd tweeted today that the recent redsn0w utility is able to jailbreak the iOS 4.1 beta2 on iPhone 3G and iPod Touch 2G. This is useful for developers only, however good news for everyone.
Here’s some info from the DevTeam wiki page:
If you’ve updated to 4.1beta2 on iPhone3G or iPod2G(non-MC), you can use this redsn0w from June to jailbreak. Just point it at the 4.0 IPSW (the public one, not the developer GM one).
(Yes – point it at the 4.0 IPSW even though you’re at 4.1beta2).
Don’t do this if you need the ultrasn0w carrier unlock!!
Note 2: If you’re at 4.1beta2 you’ll probably experience network problems after jailbreaking. Until a new version of redsn0w is released, you may need to rely on afc2 access (such as FunBox-like file browser programs) to manipulate your filesystem.
Note 3: This is recommended only for power users who can deal with the problems that will pop up as the JB apps fall further behind the beta firmwares.