HERE'S THE FIX. IT'S TAKEN ME 70HRS, ADD TO YOUR RESEARCH AND FIX.
The 2626 source clock gets stuck to SPDIF & its sample rate This causes the 2626 to be non-responsive and is then ignored by the M1 as a thunderbolt device. Don't be fooled the 2626 midi device works but no thunderbolt audio.
Here's my hack.
1. Load the universal control app.
2. Confuse the SPDIF input.
I used an DAT machine with SPDIF digital outs at 48k. Connect OUT of the digital source (dat) to the SPDIF input of the 2626. Ensure the digital output, in my case a tascam dat machine is set to digital, Connect to the 2626 SPDIF IN.
This confuses the unit and then becomes repose to thunderbolt once again, SOLID BLUE LIGHT, no restart required.
3. Go to the universal control app. The 2626 is now available once again with all the options. Change the source clock on the universal control to INTERNAL.
Now get this **** updated.
My hunch all along the new feature (1.3-86 )where the 2626 unit retains and remembers the digital settings and sync clock source.