Don't change the date to May 1970 or earlier on your iPhone, iPad
2/17/2016 at 11:59 AM
Manually changing the date to May 1970 or earlier can prevent your iOS device from turning on after a restart.
An upcoming software update will prevent this issue from affecting iOS devices.
If you have this issue, Visit an Apple Authorized Service Provider.
https://locate.apple.com/ca/en/service/?pt=3&lat=49.846927&lon=-99.952808&carrier=MTS%2520%28Canada%29