Semaphore aka @notcom – the developer of TinyUmbrella has just released version 5.10.12 of this program for both Windows and Mac.
UPDATE: Unlock your AT&T iPhone permanently. Read more here.
This latest version of TinyUmbrella has the ability to save your iPhone’s BBTicket. Some explanation on BBTicket – flashing a new baseband depends on having the correct BBTicket which can only be authorized by Apple and cannot be replayed as we do with APTickets when restoring iOS.
Any attempt to flash with baseband version lower than the one currently installed on your iPhone will fail. You will notice this when you successfully downgraded your iOS but the baseband stayed the same.
He didn’t specifically mention how they plan to use this yet, but he claims that it will be useful “later on.” He also added that BBTickets are stitched together with the SHSH files saved by TinyUmbrella. You won’t see this feature anywhere within the program as it’s done silently in the background. Be sure to check ‘overwrite saved SHSH’ as per notcom’s recommendation.
Somehow I have a sense that when you attempt to do a downgrade next time (assuming it’s 100% possible) e.g. from iOS 5.2 to iOS 5.1, the baseband gets downgraded as well. Now that would be awesome.
Although BBTicket will become less relevant as AT&T has started unlocking iPhones for free, it will still be useful for many locked iPhones locked to other carriers from different countries and for those who have got their unlock requests rejected by AT&T.
Be sure to download the latest version of TinyUmbrella directly from his website and save your BBTicket now!