LONG POST ALERT! 
AFAIK the AGESA 1.2.0.2a update specifically dealt with the Zen5 issue and iLok, and it was NOT with AM5 in general. Remember that AM5 socket supports Zen4 and Zen5, etc. Your 7950x is Zen4. The issue resolved with AGESA 1.2.0.2a was Zen5, which is 9000 series, which I can confirm works fine, as well as more recent AGESA updates.
I’m not saying that you don’t have some other issue with AM5/Zen4/iLok. After all, iLok really does SUCK IMO and I wouldn’t be surprised there’s something else going on, perhaps related, perhaps not, perhaps adjacent, perhaps not. Perhaps not specifically with iLok, but maybe the plugin you are testing, and so forth. There are TONS of variables. But AFAIK, it is probably not related to the prior AGESA 1.2.0.2a situation that plagued the Zen5 rollout. That was AM5/Zen5/iLok, not AM5/Zen4/iLok. I have tested AGESA 1.2.0.2a, 1.2.0.2b, and 1.2.0.3a Patch A, and they ALL have been working fine for me with iLok and Zen5, and no problems with latest Cubase, Nuendo, tons of iLok plugins, etc.. Since AGESA 1.2.0.2a, iLok has behaved well with many many sessions here on two systems.
BUT again, I wouldn’t be surprised if there’s something else going on, knowing iLok.
ALSO I am NOT using software-based authorization… I use the USB keys, both versions 2 and 3 of the key. Both fine. (I never use iLok’s software-based authorization, bleh, too many issues over the years for me.)
I’m not sure that’s the best approach, but if it works, go for it. You can always reinstall the later updates to compare results. FYI there are likely other improvements in the AGESA updates (as well as the additional motherboard updates in the rest of the MB manufacturer’s BIOS updates) that may improve various minor things that you might miss out on. But then again, one of those minor things might be what is causing your problem.
However, my theory is that there is something else going on that is not related to the BIOS or AGESA updates. I suspect that you have some kind of conflict between dependencies or install issues between iLok and Steinberg and/or some other plugin or app or service that may have caused a conflict. It might even just be the specific iLok plugin you are testing. So I’d suggest trying out other iLok plugins too.
Conflicts like this would not be unprecedented. Again, iLok sucks IMO, and various installers are quite capable of wreaking havoc on an otherwise stable system.
This is a clue. If you can get a crash dump you will find out what is actually crashing it, and you’ll get another clue. Follow the clues. Gather the evidence. In my experience, things are not always what they seem in this kind of situation.
Please, this is a terrible idea, I respectfully suggest you never install something like a driver-level app or system service or even just a simple plugin while you have an active session. Bad things can happen, I’ve seen corruption issues, conflicts, and other frustrations enough times in my life to never trust doing that. Installation should be a separate task, clean, and to play it safe, reboot if it is service-level/driver-level. iLok is a pain in the neck of protection system with hooks that go deeper than you may realize.
Given that I’ve seen no conflicts with Cubase/Nuendo/iLok with Zen5 and all the latest AGESA updates, my suggestion would actually be to scientifically step through a process of elimination to see if there is another potential issue. And no disrespect to you AT ALL, but given the fact that you installed iLok with an active Nuendo session going, I’ll take a wild guess that your tolerance for risk (knowingly or unknowingly) of system conflict and corruption is actually pretty high, I therefore suspect something else is at play here.
This is what I’d start with:
1 - Again, respectfully, I suggest adopting a little more caution with installing stuff on your DAW, which is a highly sensitive ecosystem of interdependent apps, drivers, and services, which are sadly capable of being screwed up fairly easily. By being more careful and scientific, and far less trusting of installers and Microsoft all getting along happily together, I guarantee you will save yourself some future headaches. I’m not saying this IS the case here, but it’s possible it is a contributing factor.
(Some people treat their high-performance DAW where they expect low latency day-in and day-out to ALSO be their everything computer and app playground and gaming rig and so forth, all at the same time, but the fact is, it doesn’t take much to throw off an otherwise stable DAW. I’m NOT saying you are one of those people, but for the benefit of other people running into this thread, one cannot assume anything about the system “usage” patterns of anyone that introduces dozens of other factors into a list of potential problems. You get my point. Again, I’m not saying you are one of those people. Nothing against those folks, who are sometimes lucky in my experience. The lucky ones should play the lottery more IMO.)
2 - Uninstall both iLok AND Nuendo. Reboot, etc…
3 - Make sure your system is updated with latest OS patches. Reboot, etc.
4 - Install another DAW – i.e. Reaper (since it is so lightweight, but whatever DAW you want)
5 - Install iLok, reboot
6 - Install the iLok plugin you want to use. ALSO install ANOTHER developer’s iLok plugin as a control/comparison case!
7 - Test the two iLok plugins in Reaper. If they both WORK, go to step 8. If they both crash, go to step 9. If ONE crashes, but ONE works… well, you have just discovered a pretty big clue about what is going on, go to step 11. Deduce from there…
8 - THE TWO PLUGINS WORK in REAPER: If they both work, it’s likely not a BIOS or AGESA problem! Continue testing…
8a - Now install Nuendo, reboot.
8b - Test the two iLok plugins in Nuendo. If both work, YAY! Congrats, the simplest uninstall/update/reinstall trick worked. If they both CRASH, go to step 10. If ONE crashes, but ONE works… well, you have just discovered a pretty big clue, go to step 11. Deduce from there…
9 - BOTH PLUGINS CRASH in REAPER: If both iLok plugins crash in Reaper, you obviously have some other conflict or issue with iLok and your system, and it is likely not related to Nuendo. It might be a BIOS or AGESA problem, but there are other steps I would explore first. Go to step 11…
10 - BOTH PLUGINS DIDN’T CRASH IN REAPER BUT THEY DO BOTH CRASH IN NUENDO: Okay, you may logically deduce there is some kind of conflict between Nuendo and iLok, but it is NOT yet solved. It could still be more complicated than that…
Why? Because Nuendo (and Cubase) and iLok ARE working fine for me and many others on AM5 so you need to explore what other potential conflicts there might be between Nuendo and iLok that are possibly unique to your system.
10a - Start with getting precise, reproducible crashes and get the darn crash log/dump and have it analyzed. The crash log/dump will give you more clues to follow, etc…
11 - AND SO FORTH… breaking things down step by step until you can get a really good perspective of what is really happening.
12 - Other tips - get crash logs, reset preferences, start DAW in safe mode, etc… lots of little things to help you gather clues.
13 - Extreme option - start from a clean system, with a clean OS installation and up. If you have a lot of apps and plugins on your DAW, you may think this is crazy and you don’t have time to do this. So one way I do this for testing is to remove the boot drive of the system and install a fresh drive and do a complete clean installation from scratch… in your case carefully install OS + drivers + updates + iLok + Nuendo + specific plugins to test = then I have a really clean system to evaluate, and I’ve eliminated most or all other installation issues. THEN in that example, you can gather more clues…
14 - And so forth. Have patience, I think you’ll get to the bottom here. Many thousands of people use Nuendo and iLok, and I know of a bunch of people quite happy with Zen4 and Zen5 in that situation. You’ll get there.
Good luck!
