MMDVM Dual Hat no longer TRX

[ke8owx]

I have a hotspot I built for my office. It is a Pi Zero W with a MMDVM Dual Hat. It was working 18 months ago (last time I used it at lunch), but now it no longer shows anything in the TRX box, and won't pass any traffic.

I did a full reformat of the card and update to the latest 4.2.1. It is a registering the modem as a dual hat with 1.5.2 firmware. I can calibrate both directions, but it refuses to allow the TRX to update. I see the display scrolling like expected, but now I'm at a loss, even after restarting from scratch. I tried both STM32 and MMDVM Dual modem selections. What am I missing?