(Like many of my technology postings, this is really here for my own notes on problems I run into, the solutions I try and what works when. They are updated as I learn.)
Not through the fault of too many bad passcodes, just started like this after update and reboot.
Turned off ipad (all the way)
Held down Home button while plugging ipad into computer. Released Home button when “Itunes” icon showed.
Itunes asked to restore. Said yes.