Problem with updating disabled iPhone
iPhone 6 just had a new screen fitted and is now disabled and saying "connect to iTunes". When trying to update the phone (from MacBook Air), a message keeps appearing after a while to say there is a problem connecting to the phone (error 9?), with a link to an apple support page with how to fix the problem. Tried all of these (updating MacBook and iTunes, changing USB cable, restarting phone and MacBook, disconnecting & reconnecting phone) and even tried using iTunes on a Windows laptop, which still didn't work.
MacBook Air has recently installed macOS High Sierra version 10.13.3 and iPhone 6 has iOS 11.2.something (not entirely sure as it has been unusable for a few weeks).
Really don't want to have to restore my phone so this is my last resort to solve this problem, there must be a way around it! Please help!! Thank you in advance:)
iPhone 6, iOS 11.2.5