Jailbreak iOS 4.2.1 on iPhone 4, 3GS with Greenpois0n RC5 on Windows

Chronic Dev Team has just released the Greenpois0n RC5 for windows to jailbreak iOS 4.2.1 iPhone 4, iPhone 3GS, iPhone 3G, iPod Touch 4G, iPod Touch 3G and iPad. The Greenpois0n jailbreak is untethered and doesn’t require SHSH blobs of iOS 4.2 Beta 3 to be saved on Cydia.

Please note that if you rely on unlock, don’t update your iPhone to iOS 4.2.1, wait until Redsn0w for Windows release.

Make sure your device is running iOS 4.2.1. If your device is running an older version, please upgrade it to iOS 4.2.1, than follow this step by step guides to jailbreak your iPhone 4 and iPhone 3GS on iOS 4.2.1 using Greenpois0n RC5.

How to Untether jailbreak iOS 4.2.1 iPhone 4, 3GS with Greenpois0n RC5

1. Download the latest version of Greenpoison for Windows.

2. Extract the Greenpoison zip file and launch the application.

3. Power off your iPhone and connect it your computer.

4. Click the Prepare to Jailbreak (DFU) button.

5. Now follow the on-screen instruction to put your iPhone in DFU mode.

• Press and Hold the Sleep button for 2 seco0nds
• Continue holding Sleep button, and press and hold the Home button for 15 seconds
• Than release the sleep button but continue holding Home button for 15 seconds

6. Once your iPhone 4, iPhone 3GS enters DFU mode, click the Jailbreak! button to start jailbreaking.

7. After the Jailbreaking process is completed, click the Quit button to close the Greenpois0n.

8. Your iPhone will reboot, than you will notice a new Loader icon on the Springboard.

9. Launch the Loader app and install the Cydia store.

10. Once the Cydia store has installed successfully on your iPhone 4, 3GS, you will be prompted if you want to remove Loader from your device. Tap the Remove button then press the Home button. Your iPhone device will now reboot.

You are done now. You have successfully untethered jailbroken iPhone 4 or iPhone 3GS  running iOS 4.2.1.

Mac users can follow these guides:

Untethered Jailbreak iPhone 4, 3GS on iOS 4.2.1 using Greenpois0n RC5 on Mac

Jailbreak iPod Touch 4G, 3G on iOS 4.2.1 with Greenpois0n RC5 on Mac

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