TinyUmbrella has been updated to version 5.10.12 for saving iOS 5.1 SHSH blobs for iPhone 4, iPhone 4S, and iPhone 4 CDMA with the added functionality to save BBTickets (baseband signing ticket). This will help iPhone users to restore to the older baseband if Apple is still signing it. Till now, it wasn’t possible to downgrade the iPhone baseband but the recent update from Notcom insinuates towards the possibility of unlocking iPhone on lower baseband (with saved BBTickets).
As noted by Notcom on his blog The Firmware Umbrella:
Save your BBTickets…
I’m pushing 5.10.12 for iPhone 4, iPhone 4s, and iPhone 4 CDMA users with functionality to save BBTickets for use later on…
BBTickets and its Significance
The device bootloaders 2.8, 2.13 (baseband or firmware) generate a random number at the time of restoring the device which is sent to Apple en-route to iTunes. Then Apple sends the APTicket / BBTicket SHSH certificate with the number generated which is matched to the number generated on your iPhone. If both the number matches, iTunes prepares the matched certificate and stitches the blobs to the firmware. If the SHSH blobs don’t match the restore process fails and the bootloaders reject the certificate.
iPhone users on iOS 5.1 Build 9B176, who seeks to unlock their device in future, should download the newest TinyUmbrella 5.10.12 and save their SHSH blobs with (APTickets/BBTickets) right away. These backed up tickets will come handy in event of downgrading the baseband after a new software update is released. Without saving baseband signing ticket, downgrade to old ipsw won’t be possible and, you will not be able to restore your device to your desired firmware version and baseband (IPSW file) using iTunes.
To download the latest version of TinyUmbrella, follow the direct links listed below or visit our dedicated download section.
Download TinyUmbrella v5.10.12 for Windows
Download TinyUmbrella v5.10.12 for Mac OS X