From Apple’s support page:
We have a workaround for you if you have an iPhone 6 or iPhone 6 Plus and you lost cellular service and Touch ID functionality today after updating to iOS 8.0.1. You can reinstall iOS 8 through iTunes by following the instructions below. We are also preparing iOS 8.0.2 with a fix for the issue, and will release it as soon as it’s ready in the next few days.
A few take aways:
1. Apple didn’t get out in front of this as quickly as they should have. They have ambitions to become a more open company. This would have been an opportunity for them.
2. The update only borked iPhones 6 and 6 Plus. All other phones were unaffected.
3. I would love to be a fly on the wall in the engineer’s offices right now.