I had this issue and this MB for years I eventually solved it by physically removing a crappy USB C PCIE card I'd bought because my case didn't have any USBC ports.
(Additionally I also previously disabled PCI wakeup buses and haven't touched it again since it's working)
Hey Tom!
This is fantastic project, I see myself using it daily. But the best part of it all is your dedication to preserving the midi culture and the art form itself.
(game) Music back then was truly on another level and I'm glad some people are archiving the songs and their chips.
open your eyes.