How did you reboot it? Did you hold it upside down and it started counting 10 down to 1?
If so i am afraid you have reset Homey completely and indeed have to set it up from scratch.
If you just powered it off and on, then try @ArnoP 's advice.
It was off for 2 hours last night inititally, to try the PTP.
This morning I replaced the adapter with a 2.0A one from an old tablet.
It booted up just fine, but I’m still missing my config.
Thanks for the help and suggestions. You guys have been really helpful, even if it wasn’t completely the answer I was hoping for.
Can’t believe this sort of thing can happen with a homey. This is something that should have been covered by some sort of feature.
I would have been happy with some sort of recovery process that requires some manual actions, but completely losing all your configuration is simply unacceptable.
I’m resolving it by switching to HomeAssistant and a USB Z-Wave dongle. If I need to reconfigure, I might as well choose a solution that allows me to properly backup things.
The homey will probably be on marktplaats soon.