Honestly I don't know what could be causing all those problems. Thought maybe the onboard 5V was wigging out, causing the USB chip to cycle on and off which would explain the disconnects, and also cycle the microcontroller and temp sensor so it keeps starting up to invalid state and blinking. But the timings don't make sense.
It's unlikely to have a bad temp sensor causing the blink. It's at least as unlikely to have a zero-chips-detected issue. It's basically impossible to have both. Did someone play baseball with it or something?
@sidehack
No the unit arrived today in pristine condition. It was very well packed. Also well protected from static. I have tried the HP PSU and a known good 20 AMP brick with it as well -- no difference -- power supply at least is ruled out
@kingofhammers
I am using an industrial pc running Ubuntu 18.04. The same exact build runs well on the NEWPAC to the same pool on the same computer.
Barring some miraculous revelation tonight, I will just send the unit back for either a replacement, or if none are available, just a refund. Thanks to all for the attempts at help with this.