Support just got back to me. They suggest to try a freshly formatted SD card. Which I did. Didn’t help.
Is there anyone with a mini for whom 1.0.1 does in fact work? Because if so I’m just going to send mine back to Thomann and request a replacement.
Update: Support says to RMA the mini.
I am now sad, because I really like having a couch device like this.
I also sent mine in.
Will take about 2 weeks.
Apparently it had to do with the usb c socket plus its going to get a new processor installed.
Fingers crossed it will work perfectly after all this.
Cause indeed its such a nice cozy couchdevice this winter.
Update: got a replacement device from Thomann. Installed firmware 1.0.1 on it and kept it running for half an hour. No crashes. Fingers crossed.
In retrospect, the box the first one came in had a bit of damage. Device itself looked fine, but maybe something had come unstuck? Probably best not to throw it around too much 
Mine came back from Poland some days ago and havent had a crash since. 
Got it back from them on 1.0.0, i upgraded to 1.0.1., all fine.
They only forgot to send all the accessories back 
which they sent seperately afterwards.
Glad to hear you had your problem fixed also.
It would be really cool if someone from Polyend would chime in here to explain how a hardware issue can cause one version of the firmware to be ok and another to crash, but I suppose they might consider that to be giving away trade secrets or something, which I guess would be understandable.
Anyway, I’m off to do some tracking!
I had crashes on both. And now on neither one, since it was a hardwareproblem with mine. (Also b stock from thomann)
Have fun!
Edit… o i see your earlier comment that you had crashes only on 1.0.1
Yeah weird!