No so old iPhone 6s has two times restarted itself with no visible reason. It looks like the iOS hangs up, the image full of artefacts is visible for one or two seconds and after that the iPhone reboots itself. I’ve tried to find if this problem is common. The issue described on the following page http://www.theinquirer.net/inquirer...e-iphone-6s-handsets-are-randomly-turning-off is not exactly the same. Is it more a hardware or software issue?