UPDATED GUIDE for iOS 4.2 Jailbreak: iPhone 4.2 jailbreak: How to Jailbreak iPhone 4.2 or iPod Touch With RedSn0w on iOS 4.2
Yesterday, to the disappointment of many anxious iOS users, iOS 4.2.1 GM was seeded to developers. Basically, this means that the OS is not ready for the public. On a good note, the updates are getting more frequent, so we should be seeing it happen soon. Apple is hoping to make it happen in November, but do keep in mind that they aren’t opposed to holding something back if they don’t feel it’s ready for the public. Much like a little piece of hardware called the white iPhone 4.
So what’s someone to do if they want iOS 4.2 now? And if they want it jailbroken? We have the answers to both your questions here.
First, a few things to keep in mind: As always, please back up your device. This is VERY important.
Also, know that you should stay away from the update if you have an unlocked iPhone.
Finally, know that Cydia does not currently work on 4.2.1. However, there is a compatible version ready to be launched as soon as the OS is released into the wild.
This jailbreak will work on the iPhone 3G, iPhone 3GS and iPhone 4 as well as the iPod Touch (2G, 3G and 4G). If you’re looking to jailbreak your iPad 4.2, check out our guide here. However, those of you with iPhone 4.2 who want the latest build, keep reading.
Now let’s get crakin’:
1) Download iOS 4.2.1 GM and the iOS 4.1 ipsw. If you aren’t in the developer program, your best bet is a Google search.
2) Plug in your iDevice and hold Option (Mac) or Shift (Windows) and click Restore.
3) You will be asked to choose a package to restore from. Find the iOS 4.2.1 GM ipsw and use it for the update.
4) Launch Redsn0w 0.9.6b2 and point it to your iOS 4.1 ipsw.
5) Check off “Install Cydia” and hit next.
6) From here, you will be instructed to make sure that your device is Off and Plugged in to the computer. The jailbreak will instruct you to exactly how go about this. Follow all the onscreen directions very carefully.
7) At the end of the process you will have an iDevice running on jailbroken iOS 4.2.1 GM firmware.