If however someone does get to a phone within that hour period, they can shove in a USB accessory and prevent the smartphone from going into restricted mode until they have a chance to attach a cracking box later on. However, if you want the update right away, you can use the Home app on your iPhone to do so. "According to our tests, this effectively disables USB Restricted Mode countdown timer, and allows safely transporting the seized device to the lab", claims Afonin. "However, we discovered a workaround..."
At any rate, USB Restricted Mode functions by preventing USB devices from connecting to your iPhone or iPad, and yes, that includes Lightning-powered accessories.
The accompanying explanation gives no indication of its real goal: "Unlock iPhone to allow USB accessories to connect when it has been more than hour since your iPhone was locked", it says underneath a sliding bar. There is detailed release note only for the iOS update, which mentions the USB Restricted Mode. Those tools end up in lawmakers' hands but, potentially, criminals as well.
iOS 11.4.1 should improve the reliability of AirPods, along with syncing Mail, Contacts, and Noes with Exchange accounts. watchOS 4.3.2 and tvOS 11.4.1 should just have general fixes and improvements.
Afonin said Elcomsoft's testing showed that most if not all third party and official Apple USB accessories could be used to bypass the USB data port locking. The device can then be accessed once again through USB.
Apple hasn't commented yet, but we can assume that a patch will be landing soon.
If you think cops won't be able to access the iPhone within the one-hour window, it appears that might not be such a big feat to achieve.