Can I Downgrade iPhone 4 Baseband 4.12.05 to 4.10.01 on iOS 6.1.3?
0
Zaied • March 24, 2013 at 2:06am
I have an iPhone 4 that was on iOS 4.3.3 with baseband 4.10.01, unlocked using a Gevey Ultra SIM. While trying to update the firmware, I mistakenly updated the baseband to 4.12.05 and now my Gevey SIM no longer works. Is it possible to downgrade the baseband back to 4.10.01 while running iOS 6 or later, or is there another solution for my situation?
Answers
0
iClarified • January 13, 2026 at 12:30am
Unfortunately, it is not possible to downgrade the baseband on an iPhone 4 once it has been updated to 4.12.05. Baseband firmware is written to a chip that does not allow for downgrading to earlier versions, regardless of which iOS version you are currently running. Since the Gevey Ultra SIM requires baseband 4.10.01 or lower, it will no longer function on your device. The best solution for your situation is to seek an official IMEI unlock. Many carriers provide official unlocks for older devices like the iPhone 4, often for free if the contract has been fulfilled. An official unlock is permanent and allows you to use any SIM card on any firmware version without the need for interposer SIMs like the Gevey.