It appears iPhones weren't the only devices having trouble with the update, either. As Brianna Wu noted on Twitter, the update has also bricked her iPad Pro.

Do not install iOS 10. It's also bricked my iPad Pro. iPhone 6S Plus will require PSU wipe. No access to calls, email, or calendar today. — Brianna Wu (@Spacekatgal) September 13, 2016

Apple, for their part, issued a statement saying: "We experienced a brief issue with the software update process, affecting a small number of users during the first hour of availability. The problem was quickly resolved and we apologize to those customers. Anyone who was affected should connect to iTunes to complete the update or contact AppleCare for help."

Of course, that's cold comfort for someone still staring down the "Connect to iTunes screen."