Take the 2-minute tour ×
Ask Different is a question and answer site for power users of Apple hardware and software. It's 100% free, no registration required.

Need help with downgrading an iPhone 4 (GSM) from baseband 4.12.01 to be able to unlock it for use with other operator than AT&T.

Have tried this guide (Downgrade iPhone 4 Baseband 4.12.01 to 4.11.08 / 4.10.01 / 01.59.00) but I only end up with an lower iOS version but no baseband downgrade

Do you know how to downgrade the baseband?

share|improve this question
add comment

1 Answer

There is no way to downgrade the baseband on an iPhone (or any Apple device, the iPad being an acception but also rife with disaster).

The only way to downgrade the baseband is to install a previous version that is still being signed by Apple. For example, if they release 5.2 today, they would be signing 5.1 and 5.2. If 5.2 came with a newer baseband, it would be upgraded once you've installed that version. If you decided to revert immediately to 5.1, it would downgrade both, the OS and the baseband.

Apple typically leaves the signing window open for only a few days. Once it's closed, you cannot alter the baseband (even if you successfully downgrade the OS).

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.