When it comes to unlocking the iPhone, definitely one of the best and popular solution is iPhone Dev-Team's Ultrasn0w. And now everyone's favorite unlock tool has just received an update. Ultrasn0w 1.2.5 is now available in Cydia.
This Ultrasn0w update is specifically for bringing in support for Apple's latest public firmware version, the iOS 5.0.1. If you have been using Ultrasn0w for quite some time now, then you should know the drill. Before you can use this tool, you need to have an unlockable baseband. But as long as you have the requirements, you should be able to unlock your iPhone 4 and iPhone 3GS running on iOS 5.0.1. Here are the supported basebands of Ultrasn0w 1.2.5.
As you can see, this new version of Ultrasn0w does not offer anything new with regards to baseband compatibility. In addition to that, it only supports iPhone 3GS and iPhone 4. Since the iPhone 4S has yet to be jailbroken, using Ultrasn0w on the device is simply not possible. But there have been buzzes that a jailbreak for the iPhone 4S will be released soon. If that is the case, then expect an Ultrasn0w update to follow.
NOTE: The only way that you can update to iOS 5.0.1 while preserving your unlockable baseband is to create a custom IPSW using the latest version of Redsn0w or Sn0wbreeze. iPhone Dev-Team frontman MuscleNerd has also advised iPhone 3GS users with old bootrom to apply Redsn0w 0.9.9b9d prior to installing the Ultrasn0w compatibility updated.