RSTn is a DW output connected to Nordic pin 25, which I stupidly set as an output instead of an input.
HEY!!! I left the board disconnected all night, and just plugged it in again. I did a reset and it now works! I unplugged it for several minutes last night, and retried to no avail. What the hell? Why would a 12 hour disconnect make a difference, over 2-3 minutes.
That is really odd. My only thought is that a charge leaked off, but that would indicate a somewhat defective device. Without knowing exactly what they are doing there’s no way to know. Do you have full control of the device; can you program RSTn as an input now?
Anyway, great news!