Untethered Jailbreak iOS 4.2.1 iPhone 4, 3GS, iPod Touch, iPad [Greenpois0n]

Recently, we had shown you how to get Untethered Jailbreak on iOS 4.2.1 with redsn0w. The method required you to have previous SHSH blobs saved and was pretty complex. Now with Greenp0ison, Untethered jailbreak iPhone 4, 3G iOS 4.2.1 is fairly easy as it does NOT require SHSH blobs for iOS 4.2b3.

Before you continue:

• Supported devices: iPhone 4, iPod Touch 4G 3G 2G, iPhone 3GS (any bootrom), iPad on iOS 4.2.1
• Greenpois0n recommends a clean iOS 4.2.1 restore. However, if you depend on unlock, do NOT update to iOS 4.1 or iOS 4.2.1 because UltraSn0w doesn’t support new basebands yet. iPhone 4 users can update to iOS 4.2.1 while preserving baseband with Tinyumbrella.
• Tethered 4.2.1 redsn0w Jailbreakers can just run greeenpois0n over it for untethered jailbreak. In case you run into problems, restore.
• Greenpois0n  jailbreak iOS 4.2.1 OTB (out of the box) iPod Touch, iPhone 4, iPhone 3GS, 3G

Untethered Jailbreak iPhone 4, 3GS, iPod Touch on iOS 4.2.1

Mac – Download Greenpois0n RC5 | Mirror

Windows  – Download Greenpois0n

Download iOS 4.2.1 (For restoring) iPad, iPhone 4, iPhone 3GS, iPhone 3G, iPod 4G, iPod Touch 3G, iPod Touch 2G

1. (Skip this step if your are not restoring to iOS 4.2.1) Connect your iPhone, iPod, iPad to iTunes using usb cable and restore to iOS 4.2.1 using the downloaded iOS firmware.

2. Run Greepois0n and hit the “Jailbreak” button.

3. Put your iDevice to DFU mode with onscreen instructions or as stated below:

• Press and hold the sleep button for 2 seconds
• Continue holding sleep; press and hold home for 10 seconds.
• Release sleep button; continue holding home for 15 seconds.

4. Greenpis0n will identify your iphone, ipod touch, ipad in DFU mode and start with the Jailbreaking process. Once completed, Greenpois0n will show the “Complete” button and your iPhone would be jaikbroken with lots of commands being sent.

5. Let it reboot, congrats! you’ve successfully jailbroken your iPhone 4 or 3GS on iOS 4.2.1. Next open the Loader app from your iPhone home screen and install Cydia.

Bingo! Now you’ve untethered jailbreak iOS 4.2.1 on iPhone 4, 3GS, iPod Touch.

iPhone 4 users with preserved baseband can proceed with unlock using ultrasn0w.

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