https://www.theverge.com/2018/7/9/17550970/apple-ios-usb-restricted-mode-iphone-passcode-cracking-bypassed-usb-accessory

Apple released iOS 11.4.1 this morning, and with it came a new software mechanism that blocks passcode cracking tools favored by law enforcement. Called USB Restricted Mode, the tool renders the iPhone unaccessible to third-party software of any kind after its screen has been locked for one hour. That way, malicious third parties or law enforcement agencies can’t break into the phone using passcode cracking tools like GrayKey.

However, researchers at cybersecurity firm ElcomSoft have found a loophole that resets the one-hour counter so long as you plug a USB accessory into the iPhone’s Lightning port, regardless of whether the phone has ever connected to that accessory in the past.