Today, we are able to confirm that the new iPhone OS 3.1 update officially disables the widely used tethering hack, at least on the AT&T network. However, we are quite positive that it has been blocked on all networks regardless of carrier.

A recent tweet on iPhone enthusiast MuscleNerd’s Twitter account revealed that those with unlocked iPhone 3G and iPhone 3G S devices need a pre-hacked 3.1 firmware with baseband 4.26.08. There will be a release with this soon.



The iPhone dev-team-blog has also stated that updating any device to OS 3.1 (iPhone) or OS 3.1.1 (iPod) will result in the loss of the ultrasn0w unlock. In fact, it may be gone permanently because for most users, the baseband firmware cannot be reverted to a previous version as it could in the main application CPU firmware.