On the phone, the tech made me do a software factory reset through the UI as if that would be better than the hardware reset. It didn't make any difference, of course, so I'll be calling them again today for an RMA.
On the technical side, when I did the reset, the router lost the time. I set the time and did a Save Settings. Guess what? The WiFi came back on without doing a reboot! What's up with that?