Just in case someone else finds it, I'm not sure what happened but a full reboot of my phone, my home server, and my AP made it detect. I think if the firmware update fails it can get *something* in a weird state where it can't be discovered. As always, turn it (all) off and turn it back on.

Did that, still no detection. Weirdly, if I try to re-pair it *now* it fails at "Configuring Node association", it just says it's unauthorized.