IPhone 7 lock that prevents individuals from attempting to replace the home button on their own. Users are now required to go to an Apple Store to have repairs done, with "recalibration" of the button being necessary. This is a step further than Apple went with iPhone 5S, 6 and 6S, where only Touch ID functionality would get disabled but the "return-to-home" functionality still worked. Some iPhone 7 devices with the model numbers A1660, A1779 and A1780 suffer from a problem where they show a "No service" message even when cellular reception is available. Apple will repair those devices for free within
IPhone on the O2 network in the United Kingdom, however, can buy the phone online and activate it via iTunes as with the previous model. Even where not required, vendors usually offer activation for the buyer's convenience. In the US, Apple has begun to offer free shipping on both the iPhone 3G and the iPhone 3GS (when available), reversing the in-store activation requirement. Best Buy and Walmart will also sell the iPhone. The iPhone's operating system is designed to only run software that has an Apple-approved cryptographic signature. This restriction can be overcome by "jailbreaking" the phone, which involves replacing the