After a day, the battery icon on screen showed up. After another day, it had actually charged to twelve percent! Wonderful. So I reset and it started smoothly.
But then I tried to log in with my iCloud account. Username, password, no problem – but with two factor authorization active, I need of course to approve the unit from another device, and enter a six digit code. But there is no window opening on the original iPad, in which to enter the code! I've tried to log in on it from several possible ways in: from iMessage, from setup, from settings > iCloud, to no avail. My other devices are happy to provide me with a code – but the original iPad gives me no opportunity to submit it. As I understand, I can't (and of course shouldn't) turn two factor off just for this one login. Any ideas, or is it a for ever lost cause?