Make sure you use a Startech 'non-bridged' Firewire card for Big Sur/Monterey/ Proxmox(VMs)
Ive used my Fireface 800 and Firewire card since 15 years without problems and during Big Sur Beta and Monterey Beta.
Sometimes you have to get your devices re-signed by Mac OS, so boot into recovery mode and delete all signed, and get it to re-register the device on next reboot by reinstalling RME fireface800 driver (user v30)
Sometime you might get a crackle sound after logging into desktop. If this happens, switch off RME, Log Out of current user account, wait a few seconds, switch on your RME again and wait for red light to go out, then Log in again. This saves having to do similar process of rebooting.
Hope this helps you guys with RME products.
