Yes, you heard it right. PERMANENTLY. This operation which takes less than 5 minutes to do will make your iPhone unusable forever. And as of now there is no way to fix that.
If you set your iOS device’s date to January 1st 1970, then reboot, your device will no longer boot up further than the Apple logo.
Even if you try to restore the device via iTunes, the device will still not work.
This affects devices with a 64 bit processor. (Apple A7, A8(X), A9(X))
But what we don’t understand is why 1970 is even an option. iOS and iPhone first came out in 2007 so this should be the lowest you can go.
This is going to be a really bad prank if you have someone who does pranks on your electronic devices, so be careful.