Previously we have seen iPhone Dev Team releasing Redsn0w 0.9.6b4 to jailbreak iOS 4.2.1 firmware. The tool can jailbreak iOS 4.2.1 on iPhone 4, 3G, 3GS, iPad, iPod touch 2G, 3G, 4G with working Cydia and MobileSubstrate. The latest version of the jailbreak tool uses Limera1n exploit instead of 24kpwn exploit as used by the previous version to pwn all iOS devices.
At the moment you can only enjoy tethered jailbreak with Redsn0w 0.9.6b4. We hope that Comex will release its untethered jailbreak for new devices like iPhone 3GS (new bootrom), iPhone 4, iPad, iPod touch 2G (MC Model), iPod touch 3G and the iPod touch 4G. Devices like iPhone 3G, 3GS old bootrom, non-MC model iPod Touch 2G can be jailbroken untethered with Redsn0w 0.9.6b4.
Stay away from from Redsn0w and iOS 4.2.1 if you are relying on a carrier unlock stay away.
How to Jailbreak iOS 4.2.1 iPhone 3GS, 3G, 4, iPod touch 4G, 3G, 2G using Redsn0w 0.9.6b4.
- Download iOS 4.2.1 for your iDevice.
- Download iTunes 10.1 for your version of iOS device.
- Download Redsn0w 0.9.6b4 for Windows and Mac
- Using the IPSW file you downloaded via iTunes 10.1 in step 1, Update to iOS 4.2.1 firmware version .
- Run Redsn0w 0.9.6b4
- Point it to iOS 4.1
- You will see the following screen as Redsn0w is now preparing the jailbreak data.
- Select “Install Cydia”
- Press Next button to start the process.
- Your device MUST be both OFF and PLUGGED IN before you click “Next”.
- A prompt will appear to allow you to put your device in DFU mode.
- First hold “Power” and “Home” button for some seconds, then release the “Power” button while holding the ‘Home” button until you see a process start for installation.
- Wait for the installation be completed.
- Your device will restart automatically after this.
This step is only for the iPhone 4, New Bootrom 3GS, iPod touch 4G, 3G, 2G, iPad Users ONLY:
- You MUST use “Just boot tethered right now” option in Redsn0w on every reboot whenever it prompts you to SSH into your device
You have successfully jailbreak your iDevice using Redsn0w 0.9.6b4 :) :) :)