If you’ve spent countless hours trying to find the right answer, don’t look any further because I’ll give you the straight answers here.
Trying to find an online solution to unlock your iPhone 3GS can be a daunting task. Firstly, if you’re new to jailbreaking and unlocking iPhones, you will be confused with so many technical terms used. This is made worse with the amount of free tools available out there – sn0wbreeze, redsn0w, blackra1n, Absinthe etc. Which tool should you use and which one would work the best for you?
Here are the straight answers for you:
1. iPhone 3GS made after week 28 of 2011 cannot be unlocked using any available software method. Full stop. However, anything made before that can be unlocked by downgrading the baseband to 5.13.04.
2. Here’s how to check if your iPhone 3GS is made before or after week 28 of 2011.
3. Baseband version that cannot be unlocked are: 5.14.02, 5.15.04, 5.16.02, 5.16.05 and 5.16.07.
4. Referring to (1), if you have an older iPhone 3GS, you have the option to unlock it by installing iPad baseband 6.15.00, and then downgrading it to 5.13.04. Unfortunately, there’s no way to downgrade from baseband version mentioned in (3) to 5.13.04. You MUST update to 6.15.00 first (you can do all these with redsn0w 0.9.15b2).
5. The best way to unlock an AT&T iPhone 3GS made after week of 28 of 2011 is using this official unlock. It’s simply your best choice and will end all your unlocking nightmare. Do note that it supports older 3GS too, but you must downgrade to 5.13.04 first otherwise when you update to iOS 6, you won’t be able to activate it.