A newly discovered bug renders iPhones useless if the system date is set to January 1, 1970. 
 
 Why would anyone purposely set their phone to a date 45 years in the past? Well, one possibility is that they've been fooled by a troll. 
 
 The above image was posted to notorious anonymous forum 4Chan on Thursday, and has been spotted on Facebook and Reddit. 
 
 Anyone changing their iPhone's date hoping for a delightful rainbow-colored Apple logo easter egg will soon discover their phone refuses to boot up. It can't be fixed except by an Apple Store, which will most likely simply offer a replacement. 
 
 The bug is related to a very old, well-documented issue with the Unix class of operating systems on which Apple's iOS is loosely based – it's similar to a Facebook glitch that prompted its users to celebrate "46 years of friendship" in December. 
 
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 Feb. 12, 2016, 8:52 PM GMT / Updated Feb. 12, 2016, 8:52 PM GMT By James Eng 
 
 Want to go back in time to January 1, 1970? Just make sure you don’t do it on your iPhone. 
 
 Changing the Date & Time settings to that fateful date will disable your device, Apple users report. And good luck trying to get it to restart: Connecting the disabled phone to your computer and trying to reboot it via iTunes won’t work. 
 
 One chagrined user posted about his device's demise on an online Apple help forum: 
 
 "Hello, I was playing around with my Date & Time settings and I changed the time to January 1st 1970. I shutdown my phone and restarted it, the result is a bricked iPhone. I've tried restoring, updating, but nothing seems to be working." 
 
 Tech website 9to5mac posted a video demonstrating the date bug, which appears to only affect Apple devices with 64-bit processors — meaning iPhone 5S, iPad Air, iPad Mini 2 and the sixth-generation iPod Touch, or newer models of those devices. Trying to restart the device seems to only bring back the Apple logo screen, where it apparently gets permanently stuck. 
 
 Apple hasn’t responded to a query from NBC News about the apparent bug. 
 
 Related: Apple Says 1 Billion of Its Devices Are in Active Use Around the World 
 
 What's so special about 1 January 1970? Techie commenters on Reddit and elsewhere note that’s the start of Unix time, a way for developers to track time as a running total of seconds. Manually setting your Apple gadget to that date apparently causes a conflict that will chock the device.
– Setting your iPhone's date and time to Jan. 1, 1970, will instantly make you experience what life in the '70s was like—because you'll no longer have a cellphone. "I changed the time to January 1st 1970," NBC News quotes one poor iPhone user's complaint to Apple. "I shutdown my phone and restarted it, the result is a bricked iPhone. I've tried restoring, updating, but nothing seems to be working." Wired reports it's a bug that appears to be affecting 64-bit iOS devices, such as the iPhone 5S, iPad Air, and other newer models. Moving an iPhone's date setting back by 46 years isn't something most people would do without some prompting. So, of course, there's been some prompting. An official-looking promotional image popped up on the 4Chan forum on Thursday before spreading to Facebook and Reddit, Business Insider reports. The image instructs people with iPhones to change the date to Jan. 1, 1970 for a fun "easter egg": a rainbow-colored retro Apple logo when the phone is rebooted. Instead, the phone refuses to start back up and requires either a physical fix or complete replacement. So what's causing this odd bug? "It’s almost certainly related to the same Unix glitch that caused Facebook to wish people a happy 46 years on the service," Wired states.