Haven't figured out the process or what the failure is yet... but...
* Left Obi off overnight
* Plugged in, and it booted!
* Unplugged and moved to the room where I needed it to be...
* And... fail. Will not boot. With or without the ethernet cable plugged in, so it has nothing to do with DHCP.
* Waited half dozen hours, and it booted again! Had to do a few hard resets
* Wasn't able to configure it through the portal due to lack of time
* Half dozen hours later... it was dead again
* Spent quite a bit of time booting, and rebooting, and pressing the factory reset button, and...and...and
* And finally, it booted again, and I was able to configure it correctly
So... for anyone else experiencing this problem with an Obi, for now my recommendation is:
* Leave it unplugged overnight or for a day
* Factory reset (with the pin on the back) on first boot
* Hope for the best