How to Unlock or Activate iPhone 4 Stuck on Baseband 4.12.02
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regalman • November 24, 2012 at 4:11am
I purchased an iPhone 4 running iOS 6.0 with baseband 4.12.02, which seems to have been used with a Gevey SIM. I cannot set up the phone because iTunes requires a valid SIM card for activation. I want to restore it to stock firmware and the original baseband to perform a factory unlock. I have tried downgrading to iOS 5.1.1 and using tools like sn0wbreeze and redsn0w, but nothing is working. How can I resolve this?
Answers
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iClarified • January 12, 2026 at 3:52am
Baseband 4.12.01 and 4.12.02 on the iPhone 4 are not supported by software unlock tools or hardware interposers like the Gevey SIM. Because these basebands cannot be downgraded, the only way to factory unlock the device is through an official IMEI unlock from the original carrier or a third-party service. To get past the activation screen without a valid SIM, you can use redsn0w to hacktivate the device, which allows you to access the operating system, though this will not enable cellular functionality. For a full restore to stock, use iTunes to restore to the latest available iOS version for the iPhone 4. If the device is IMEI unlocked, it will activate successfully with any SIM card during the setup process.
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datumax • November 24, 2012 at 4:34pm
The Gevey Ultra SIM is not compatible with baseband 4.12.02. For this specific version, the most reliable solution is to obtain a permanent IMEI unlock. This will allow you to activate the device with any SIM card and restore to stock firmware without needing to bypass activation screens or use hardware interposers.