MuscleNerd of the iPhone Dev Team has reconfirmed that it will be possible to unlock the new baseband (05.13.04) that is included in iOS 4 Golden Master and that it might be possible to also unlock iPhone 4.
Two weeks back iPhone Dev Team had confirmed that they will release tools to unlock iPhone OS 3.1.3 and iPhone OS 4.0 now renamed as iOS 4.
When MuscleNerd was asked a question about unlocking iPhone OS 3.1.3 and baseband 05.12.01 that’s included in it, he responded with the following tweet:
yep…the final 4.0 next week will be an even later version and is confirmed unlockable (possibly iPhone4 too)
So if you depend on the software solution to unlock your iPhone then it is recommended that you wait for iPhone Dev Team to confirm before upgrading to iOS 4 when it is released on Monday, June 21.