TinyUmbrella lets you update iPhone 4 to iOS 4.2.1 while preserving its baseband version 01.59.00 which can be unlocked using Ultrasn0w. Below is a guide on how to update iPhone 4 to iOS 4.2.1 firmware while preserving baseband 01.59.00 using TinyUmbrella. Updating iPhone 4 to iOS 4.2.1 also updates your baseband to 03.10.01 which is currently NOT unlockable with Ultrasn0w.






However, if you update your iPhone 4 to iOS 4.2.1 while running TinyUmbrella TSS server, it’ll preserve its baseband 01.59.00 and update iOS 4.2.1. Lets learn how to use TinyUmbrella to update iPhone 4 to iOS 4.1 while preserving baseband 01.59.00.

Note : This method applies to iPhone 4 only. iPhone 3GS and 3G users MUSt stay away from it and wait for an UltraSn0w update. I have tested this method myself on my iPhone 4 and it works like a charm.



Update iPhone 4 To iOS 4.2.1 + Preserve Baseband 01.59.00 [How To] :

1) Download TinyUmbrella 4.21.05 and iOS 4.2.1 for iPhone 4 from links below.


2) Run TinyUmbrella.

3) Hit the Save SHSH button and make sure iPhone 4 iOS 4.2.1 SHSH blob is listed. Now, Hit the Start TSS Server button. It will kill iTunes.

4) Now open the iTunes. Hold down the SHIFT (Windows) or Alt/Option (Mac) key and hit the Restore button in iTunes.

5) Browse and select the iOS 4.2.1 firmware.

6) Let iTunes give the 1013 error (baseband update failed)

Now, you have successfully updated iPhone 4 to 4.1 with 1.59.00 baseband. Now follow the link below to get out of recovery mode and jailbreak iPhone 4 with Greenpois0n.

Jailbreak iOS 4.2.1 With greenpois0n RC5 [How To]