This guide explains how to update your iPhone 4 to iOS 4.3.1 safely without upgrading baseband. You will also read why it is important to preserve iPhone 4 baseband if you want to unlock your iPhone 4. Ultrasn0w is yet to be updated to support unlocking on iOS 4.3.1 but the untethered jailbreak has already been released.
This tutorial will show you show how to update iPhone 4 to iOS 4.2.1 without upgrading your baseband. This method will preserve iPhone 4’s baseband at 1.59.00 so you don’t lose your software unlock using Ultrasn0w in case you don’t have a factory unlocked iPhone.
By usin Cydia Make my life easier, thanks button you can quickly save your iPhone 3Gs, iPhone 4, iPad and iPod Touch 3G SHSH blobs. In this tutorial I will be guiding you how you can use TinyUmbrella to save iOS 4.X+ SHSH blobs.
Click on Save SHSH and if you wish you can change location of file by going under advanced tab.
Within Seconds your SHSH blobs would be saved. If you have a jailbroken iPhone with 4.x+ iOS, make sure you do this step ASAP. As iOS 4.2 is coming soon for everyone. You can check under logs to find if your SHSH blobs was saved in cydia or not.