iOS 5 was jailbroken soon after release. Jailbreaking allows you to run 3rd party apps on your iOS device that haven’t been approved by Apple for distribution through the office iTunes App Store. Unlocking builds on jailbreaking to remove the carrier lock for your GSM iOS device. For example, US iPhone owners who want to use T-Mobile, rather than AT&T have to used an unlocked phone.
Well, hold on to your seats! You saw it here first (unless you didn’t)! iPhone 4 and iPhone 3GS owners can now unlock their phones running iOS 5! For more details, check out this helpful post about UltraSn0w 1.2.4, which makes it all possible.
Be careful though, don’t rush to upgrade to iOS 5 you need to be careful about what version of the baseband code you are running!
Yes, the iPhone Dev Team is just that awesome. They’ve released updates to RedSnow, their easy jailbreaking tool, and UltraSn0w, their iPhone 3G and now 3GS unlocking tool.
With this combo, you can jailbreak your iPhone to run unofficial 3rd party applications with RedSn0w (thats RedSn0w, with a zero). Then you can use one of those unofficial 3rd party applications called UltraSn0w (again, with a zero) to unlock your phone so you can use it with a 3rd party GSM carrier.
Note: Don’t go rushing to install the 3.1 firmware that is in beta now. Baseband upgrades can break your unlock and may make it impossible to ever unlock again.
If you have an unlocked iPhone 3G you can now take advantage of the new 3.0 firmware! First, use RedSn0w (that’s a zero in there, not an ‘o’, to jailbreak your phone, then use UltraSn0w to unlock it! For more info on UltraSn0w, go to the source. This apparently supersedes the original YellowSn0w unlock for the 3G.
Note, this doesn’t work with the 3.1 firmware betas that are being circulated, at least not yet.