Though people have to go out of their way to trigger it, a time-related glitch discovered in iOS 8 and 9 will let users potentially "brick" many Apple devices, rendering them non-functional. Many users have discovered that if you change your device to January 1st, 1970, your iOS device will be permanently bricked. The video of the process is below should you wish to try it out however we recommend you to not try this as this video is for educational use.
In order to change your date and time settings, you have to go to the Settings app, tap the General menu, choose Date & Time, and turn off the Set Automatically option. From there, you’ll have to scroll through the menu until it reaches as far back as it goes. After that, go back to the General menu then go back into the Date & Time settings and scroll backwards again. You’ll have to repeat this process until you reach 1970. The video specifically shows how to do this.
After you successfully set your iOS device’s date to January 1st, 1970, you’ll then want to reboot your phone and book a trip to the Apple Store. Once you reboot, your device will reportedly not come back on. You can put it into DFU and even get iTunes to recognize it to perform a restore, but even after that, it will remain stuck on the boot up screen.
The bug affects any iOS device that uses a 64-bit processor and is running iOS 8 or newer, including iPhones, iPads, and iPod touches. For those unsure, 64 bit processors are the A7, A8, A8X, A9, and A9X (iPhone 5s or later, for instance). If you use a 32 bit device however, you’re in the clear.
A Reddit thread offers a handful of possible causes of the issue. The most reasonable appears to be that it all comes down to time zones and that setting the date to January 1st, 1970 causes the internal clock to be set to less than zero, which confuses the device and crashes it.
One Twitter user says that the device could come back on after 5 hours, while another notes that changing the SIM card could fix the issue, as well. Other users, however, say that it has been longer than 5 hours, some upwards of a day, without the device coming back on. If you’re device comes back on after 5 hours, expect it to be very laggy, but you should be able to go into Settings and change the date back.
For those who got away with trying this and it not bricking your device, there's a reason why - time zones.
In some time zones, setting the date to 1 Jan 1970 will set the internal clock to a number less than zero, as the time is stored in GMT (as the number of seconds since midnight on that date) and then the offset is applied before display. In other time zones, setting the clock will result in a positive time value. Best guess is that this is triggered by having the time value less than zero.
If you do however choose to try this glitch trick, please let us know in the comments system below.