Hey guys my DEEPEST APOLOGIES for not updating this post earlier this summer in my plans to test Sonoma Dev Beta with FF800. It didn't 100% work at first in July, and I was disheartened but then found there was a bug in Thunderbolt-to-PCI chassis (how I use my FF800) driver instantiation in Sonoma Beta. That got fixed in late July or Aug, and I was able to see/use my FF800 just fine as always, on my test machine.
Today I further confirmed this by moving my main rigs (Mac Studio and MBP 14 both M1 chips) to the released Sonoma and my FF800 works fine from both. Here is the caveat to my particular FF800 Chain -- because I doubt using ANY Apple Firewire adapters would EVER work going forward. This is how I am working with FF800:
My main connection chain is a Mac Studio M1 Ultra (and MBP 14 M1 Max at other times) ---> Thunderbolt to PCI Chassis ---> TI chip-based FireWire 800 PCI Express card ---> RME FF800.
Further, on Apple Silicon Macs you MUST take an additional step to enable the RME System Extension: you MUST reboot and adjust your driver extension security level using the Startup Security Utility -- if you don't, neither Ventura nor Sonoma allows the FF800 System Extension (kernel driver) to load. MacOS Ventura/Sonoma actually walk you through the steps, after FF800 driver installation completes - but Apple / RME are not going to bail you out if you cannot do this step (it worked for me on two Macs). Note: if you already did this on Ventura in the past year, you won't have to do it again after Sonoma upgrade.
RME info for doing the above reboot steps (only needed for legacy drivers, btw, their current drivers do not need this) for the Startup Security Utility is here:
https://www.rme-audio.de/rme-macos.html/
Note: this technically, according to Apple, reduces your Security somewhat (because modern Malware may try to install unsigned System Extensions). The remedy for this is: don't EVER install anything unsigned, other than these drivers, EVER. And you will be fine. If your Studio setup has other people installing things from all over the place - then I don't know what to tell you.
The above is how I got all this to work in Ventura, and now Sonoma. And, again, I did not have to re-install the last RME drivers or anything on existing systems (nor did I have to re-do the Security Startup Utility steps above -- that is only needed on fresh driver installs). So if you already had FF800 working on Ventura, you're golden and good-to-go for upgrading. As always, YMMV and I advise that you make sure you always check the TotalMix forum in here, to download the latest updates to Mac version of TotalMix -- because the last FF800 drivers (released in 2021) contain and older version of TM. And, OF COURSE, always back up before upgrading your MacOS!!
So, to recap, we MacOS FF800 users live to fight another year -- with the connection chain above, anyway. I really doubt Firewire adapters will work anymore, but PCI chassis w/ a TI chip-based PCI Firewire Card DOES.
But DO REMEMBER: Apple officially does not support Firewire peripherals, and this is an EOL interface (as gloriously beautiful and powerful as it still is...) and functions on borrowed time. So our blessing could go away at ANY TIME with ANY future MacOS update (including Sonoma updates). So, always back-up your system, and be cautious and test.
If Apple keeps this loophole (PCI --> Firewire 800 cards) working -- RME may have to just bite the bullet and give us a discount program to turn in our trusty FF800s for their latest-gen gear. lol
Peace out, and good luck everyone!