Apple pushed iOS 4.2.1 GM build for developers and guess what? iOS 4.2.1 is vulnerable to Redsn0w 0.9.6 b2 released by iPhone dev team. You can jailbreak your iPhone 3G, iPhone 3GS, iPhone 4, iPod Touch 2G, iPod Touch 3G, iPod Touch 4G and iPad running on iOS 4.2. Needless to mention, but if you use Ultrasn0w to unlock your phone should stay away from Apple Stock Firmware update and Redsn0w.
NOTE to Jailbreakers : Don’t install cydia because it’s not compatible with iOS 4.2, if you are not a developer than stay away. Also remember that the Golden Master version is dedicated only to developers, then we do not recommend the use of end-users should wait for public release.
- Redsn0w 0.9.6b2 (download here)
- iTunes 10.1
- iDevice with iOS 4.2.1 on board.
The procedure is virtually identical to the iOS 4.1 jailbreak procedure, the only difference is that after updating your iDevice to iOS 4.2.1, it is necessary to point “iOS 4.1 firmware and not the iOS 4.2.1 GM”
1. Launch RedSn0w 0.9.6b2, click on select and browse for iOS 4.1 (don’t browse for iOS 4.2.1) and after that the program has identified the firmware, will begin a quick process ( Internet connection required).
2. Don’t select “Install Cydia” and then click Next again.
3. Now you’ll be asked for some tweaks and options depending on the device you are using.
4. Redsn0w will patch and install some files to your iDevice.
5. Follow the onscreen instructions to put your iDevice in DFU mode when prompted and your device will be properly jailbreak in seconds. That’s it.