Update your iPhone 4 to 4.2.1 while preserving its 1.59.00 baseband using TinyUmbrella

Just Recently, The Chronic Dev Team has released the much awaited Greenpois0n RC5 for untethered jailbreak on iOS 4.2.1 iPhone 4, 3GS, iPod Touch 4G, 3G. But for unlocked iPhone 4 users it is useless because the updated baseband can’t be unlocked using the current Ultrasn0w version.

Fortunately, TinyUmbrella developer, Notcom come up with a new way to update your iPhone 4 to iOS 4.2.1 without upgrading the 1.59.00 baseband, so later you can unlock your iPhone 4 again with Ultrasn0w.

Follow this guides to protect your iPhone 4 baseband and update it to iOS 4.2.1.

how to upgrade your iPhone 4 to 4.2.1 while preserving its baseband with TinyUmbrella

1: Download TinyUmbrella from here.

2: Connect your iPhone 4 to Mac & Launch TinyUmbrella.

3: Launch TinyUmbrella and click On the “Save SHSH” button.

4: Now, Hit the “Start TSS Server” button. TinyUmbrella will check your SHSH blobs of the latest firmware on Saurik’s server and will also save your computer.

5: Launch iTunes and click on Restore in iTunes (Don’t Click on Update)

6: During the Restore Process, iTunes may give you Error 1013. This error means your baseband has been preserved, than close iTunes and its all errors.

7: Next, click the Exit Recovery to kick your iPhone out of Recovery Mode.

8: jailbreak your iPhone 4 iOS 4.2.1 on 01.59.00 baseband with Greenpois0n RC5 (follow the guide here).

Now you are able to carrier unlock your iPhone 4 iOS 4.2.1 using Ultrasn0w unlock.

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