Untethered jailbreak is available for all devices with iOS 6.0 – iOS 6.1.2. This includes:
If you don’t need cellular unlock use Evasion utility, tutorials are available here:
If you need custom firmware to preserve baseband modem version for iPhone unlock use SnowBreeze. Tutorials are here:
The iPhone Dev-Team has released UltraSn0w 1.2.8 to bring unlock support for some older basebands on iOS 6.1.
MuscleNerd commented in twitter:
Version 1.2.8 is compatible with 6.1 main firmware
This is the tweet from MuscleNerd posted a minute ago. So it is just minutes to wait for new unlock utility ultrasn0w.
UPDATE: New ultrasn0w released! New PwnageTool 4.1.3 released. Read carefully from DevTeam first, then reread again!
UPDATE 2: new ultrasn0w 1.2 supports the following basebands:
UPDATE 3: Step-by-step Tutorial: How to Jailbreak and Unlock
MuscleNerd has recently announced via tweeter that ultrasn0w unlock for iPhone is now fully working on iOS 4.2.1
Finally got ultrasn0w working fully on 4.2.1. Apple inadvertently(!) broke ultrasn0w via aggressive compiler optimization
MuscleNerd previously announced that the ultrasn0w unlock should be available by Sunday for the iPhone 3G and iPhone 3GS. The unlock for the iPhone 4 will take much more time.
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.