error 4000
I received the error 4000 iPhone cannot be updated. Unknown error has occurred (4000). I was updating the itune and this happened.
Windows, Windows 6
If you see an error when you update or restore your iPhone, iPad, or iPod - Apple Support
Make sure iTunes it up to date. If there is an update for iTunes, try that.
Otherwise I have read elsewhere for error 4000 that you may need to either make sure the iPhone stays awake while updating or you may need to remove the iPhone passcode and then try updating.