How to update a jailbroken iPhone 4 while preserving the baseband
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Trancemaker • December 10, 2012 at 1:20pm
I have an iPhone 4 on iOS 4.2.1 that is jailbroken and locked. I am currently using a Gevey SIM for my cellular connection. How can I update my firmware to a newer version like iOS 5.1.1 or iOS 6 while preserving my baseband so I don't lose my unlock status? Every time I try to restore using a custom IPSW, I encounter verification errors with Apple's servers.
Answers
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iClarified • January 12, 2026 at 4:09am
To update a jailbroken iPhone 4 while preserving your baseband for a Gevey SIM unlock, you must use a custom IPSW. This prevents the baseband from being updated to a version that is incompatible with your interposer. 1. Download the firmware (IPSW) you wish to install. Note that you can only restore to firmware versions that Apple is currently signing, or versions for which you have saved SHSH blobs. For the iPhone 4, the final supported version is iOS 7.1.2. 2. Use a tool like Redsn0w or Sn0wbreeze to create a custom IPSW. Select the option to preserve the baseband. 3. Put your iPhone into Pwned DFU mode using Redsn0w or iREB to avoid iTunes errors like Error 1600. 4. Open iTunes, hold the Shift key (Windows) or Option key (Mac), and click Restore. Select your custom No_BB IPSW. If you are trying to install iOS 5.1.1 and Apple is no longer signing it, the verification error occurs because you lack the necessary SHSH blobs. Without blobs, you will be forced to update to the latest compatible version, which is iOS 7.1.2.