OpenCore, BigSur and FireWire Audio

[TS200010]

I have upgraded my rig from Catalina to BigSur and the FW Audio output has stopped working. The Audio I/F shows up but nothing comes out of the speakers. Its not the wiring or related as when I boot into Catalina then the sound works with no other changes. Its and old system (Onyx Blackbird) but as the devices show up in About and Audio MIDI Setup I would expect sound to come out!

Sound does go the other way - from the Audio Interface into the PC... so where am I going wrong!

 

[Edhawk]

A device showing up in System Information or Audio Midi Setup, doesn't automatically mean it will work in macOS. Just that the device is recognised, it doesn't mean the kext required is being injected or working.

Questions:

1. Were the kexts used in Catalina to play through the Audio interface removed from Big Sur?
2. If they are third-party kexts/drivers are they compatible with Big Sur?
3. Are the kexts injected by your boot loader (Clover or OpenCore)?
4. Have you tried to install the kexts to one of the system folders /L/E or /S/L/E? This no longer works, so hopefully you haven't gone down this route.
5. Do you still have Catalina installed on a drive, that you can use to see what is different between the two OS's when using/connecting your Audio interface?