If you want to enjoy full untetheted iOS 4.2.1 jailbreak on your iPhone 4, you must jailbreak it with GreenPois0n RC5 tool. As a pre-requisite, GreenPois0n requires iOS 4.2.1 pre-installed on the iPhone so that it may flash the Limera1n exploit on it. In order to upgrade your iPhone 4 to iOS 4.2.1 while preserving its baseband, you can either use PwnageTool bundles or the TinyUmbrealla software. Unlike PwnageTool, TinyUmbrella is availble for both Windows and Mac OS X, so the following guide is effective for both Mac and Windows users.
Steps to Upgrade iOS 4.2.1 on iPhone 4 Using TinyUmbrella:
NOTE: The method below is strictly for iPhone 4 users only. If your iPhone 4 is running iOS 4.x.x (NOT 4.2.1) and have baseband 01.59.00, you may proceed to the guide below:
- Download and install iTunes 10.1.1 for Windows or Mac OS X from here
- Download TinyUmbrealla software for Windows or Mac OS X from here [Win | Mac]
- Download iOS 4.2.1 firmware for iPhone 4 from here
- Download GreenPoi0n RC5 for Windows or Mac from here
- Plug your iPhone 4 to your PC with a USB cable and start TinyUmbrella software.
- Select your iPhone from the side-panel and click on the Save SHSH button.
- Wait while TinyUmbrella saves your iPhone SHSH blobs locally on your hard disk drive.
- Once all SHSH blobs are saved locally, click on the 'Start TSS Server' button.
- Once TSS server has been started, you will see the following message:
- Under the console section, see if there is any error. If there is an error, unfortunately you cannot proceed to the restore, however if TSS Server is running successfully without any error, proceed to the restore steps below.
- Start iTunes 10.1.1. Hold down the SHIFT key (ALT on Mac), click on the 'Restore' button and choose iOS 4.2.1 IPSW you downloaded in step 3.
- Click on the 'Restore' button and wait while iTunes restores iOS 4.2.1 on your iPhone.
- If iTunes throws error 1013 during the restore, it means your baseband is not upgraded. This is what we actually wanted, iTunes error 1013 means you have successfully restored your iPhone 4 to iOS 4.2.1 while preserving its baseband. In case you end up in error 16xx, put your iPhone in DFU mode and jump to step 11.
- Put your iPhone into DFU mode by using the following instructions:
- Press and hold sleep button for 3 seconds.
- While holding the sleep button, press and hold the home button for 10 seconds.
- After 10 seconds, release the sleep button but keep holding the home button for 15 seconds.
If you faced any issue in following the above tutorial, please feel free to comment below.Contact Us for News Tips, Corrections and Feedback