On acer switch 11v, i was able to update with update assistant tool, with a few errors on restart. Eventually got it, and restarted a few times after just fine. But i shut down completely, and thats when problems started. It would never boot up. Eventually forced to use recovery drive, but did little to help. Tried startup repair, fix mbr in command prompt nothing worked. Still wouldn't boot from a complete shutdown. Forced to do a fresh install. Then i updated to 1803, which was fine. But when i tried to update to 1809 again, same thing. It would never boot up from a complete shutdown. So did a fresh install again, now on 1803 again til this gets sorted out.
I'm having the EXACT same issue on the same machine. A few of my students are claiming their devices did Windows Updates last night now the machine freezes on startup!
I'm still on 1803 now, my machine won't let me update to 1809 anymore even when I do a "check for updates", which leads me to believe that at least Microsoft is aware of the problem, or at least has detected that my machine has done a bad update in the past. But the fact that it allows your students to update is worrisome, in that it doesn't flag specific models as troublesome, only users who have had unsuccessful udates?
Curious - what version of windows 10 are you on? My HP Spectre (Win 10 Pro) is doing the same as yours it appears. !809 is not being offered.