IPhone 6 the display. To accommodate the larger physical size of the iPhone 6 and iPhone 6 Plus, the power button was moved to the side of the phone instead of the top to improve its accessibility. The iPhone 6 features a 6.91 Wh (1810 mAh) battery, while the iPhone 6 Plus features an 11.1 Wh (2915 mAh) battery. Unlike the previous model, the rear-facing camera is not flush with the rear of the device, but instead protrudes slightly. Both models include an Apple A8 system-on-chip, and an M8 motion co-processor—an update of the M7 chip from the iPhone 5s. The primary
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