Upgrading a Jailbroken iPhone 4 to iOS 5.1.1
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marcrwno1 • December 19, 2012 at 3:25pm
I have a jailbroken iPhone 4 on iOS 4.0 with baseband 01.59.00. I would like to upgrade to a version of iOS 5 to use modern apps while maintaining my untethered jailbreak and preserving my baseband for unlocking purposes. I am currently confused about how to use unsigned IPSW files and SHSH blobs to complete this process safely.
Answers
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mateen • December 23, 2012 at 11:09pm
To upgrade your iPhone 4 to a version of iOS that is no longer being signed by Apple, such as iOS 5.1.1, you must have your SHSH blobs saved for that specific firmware. You can verify your blobs using the steps in this guide: www.iclarified.com/16988/how-to-save-your-iphone-shsh-blobs-using-redsnow-mac. Since you have the 5.1.1 blobs and an iPhone 4 with the 01.59.00 baseband, you should use Redsn0w to create a custom IPSW. This custom firmware will allow you to stitch your blobs to the IPSW and prevent the baseband from being updated, which is crucial for maintaining a carrier unlock. 1. Download the iOS 5.1.1 IPSW for the iPhone 4 and the compatible version of Redsn0w. 2. Use the Extras section in Redsn0w to stitch your SHSH blobs into the firmware file. 3. Put your device into Pwned DFU mode using Redsn0w. 4. Open iTunes and perform a restore by holding the Shift key (Windows) or Option key (Mac) while clicking Restore, then select your custom IPSW. 5. Once the restore is complete, use Redsn0w to perform an untethered jailbreak. 6. If you require an unlock, install ultrasn0w from Cydia after the jailbreak is finished.