How to Install iPad 6.15.00 Baseband to Unlock iPhone 4?

Hello Gabriel, sad to say, but there’s no way you will be able to update the baseband of your iPhone 4 to iPad’s 6.15.00 baseband as this hack is available only for iPhone 3GS. If this process is possible for the iPhone 4 users, then the iPhone Dev Team will have definitely announced this to the public. The best and reliable option available in order to unlock your iPhone from its contracted mobile phone carrier is by unlocking your device using Gevey SIM – a hardware-based unlocking tool that works on almost all iPhone firmware and baseband.

Anyway, to unlock your iPhone using Gevey SIM you will need to hacktivate your device by jailbreaking it using Redsn0w. You can get Redsn0w 0.9.6RC19 for Mac OS X using this link or from here if you are on Windows. Then check this blog post for the detailed jailbreak tutorial using Redsn0w. After jailbreaking, you will need to activate your iPhone using your AT&T SIM card or though SAM. The guide on how to activate iPhone using SAM can be found here. Then once jailbroken and activated, you can refer on this guide on how to unlock iPhone 4 on iOS 4.3.3 using Gevey SIM Pro. Oh, by the way, don’t forget to save the SHSH blobs of your device using iFaith SHSH Blobs Dumper.