Apple is aware of and investigating an iPhone 7 and iPhone 7 Plus issue that can result in the loss of cellular service after turning off Airplane Mode on the devices, according to internal documents obtained by MacRumors.
In the meantime, Apple has advised authorized service providers to instruct customers to restart the affected iPhone 7 or iPhone 7 Plus. If no service persists, Apple advises customers to remove and re-insert the device's SIM card.
In a video shared with MacRumors by reader Yasser El-Haggan, an iPhone 7 can be seen with no service alongside an iPhone 6s with two bars of LTE after Airplane Mode is toggled off on both devices. Both of the iPhones are said to be AT&T models, which means the iPhone 7 has an Intel modem rather than a Qualcomm modem used for Verizon and Sprint models.
All of a sudden today my iPhone 7 Jet Black model started not getting internet service -- can’t make outbound calls or receive calls -- even though it showed 4 bars. I then put it in Airplane Mode, and back off, then it showed no service. It got pretty warm in the top right hand corner.
I then took a video of my wife's iPhone 6s right next to my iPhone 7, put them both in Airplane Mode, and then switched Airplane Mode off and you can see immediately that the iPhone 6s gets signal instantly, and the iPhone 7 just sits there searching. I then took her SIM and put it in my iPhone 7, no luck, put my SIM in her phone, and it got signal right away.
El-Haggan said he took his iPhone 7 to an Apple Store, where the Genius Bar swapped out the device with a new one. The employee had allegedly seen the issue on a few previous handsets, and he immediately replaced the device per Apple's instructions in lieu of running a basic diagnostic test. Apple appears to have replacement iPhone 7 models reserved for these scenarios per standard policy.
