There’s a mysterious issue affecting iPhones. The Daily Dot’s Mike Wehner happened across it when he tried to update his iPhone 6 Plus to iOS 8.3. The iPhone wouldn’t install the update, and when he tried connecting it to iTunes to update, he was presented with error 53. After that, the iPhone entered a reboot loop, which rendered it unusable. Error 53 isn’t mentioned in Apple’s list of numerical error codes, and Genius Bar employees seem unaware of it. So far, the only fix has been to replace affected iPhones.