Workaround per risolvere il problema:

We have a workaround for iPhone 6 and iPhone 6 Plus users who lost cellular service and Touch ID functionality today after updating to iOS 8.0.1. Affected users can reinstall iOS 8 through iTunes, for more information visit Loss of cellular service or ability to use Touch ID after updating to iOS 8.0.1 on iPhone 6 or iPhone 6 Plus. We apologize for the great inconvenience experienced by users, and are working around the clock to prepare iOS 8.0.2 with a fix for the issue, and will release it as soon as it is ready in the next few days.