Unable to modify AVR's EDID (I could previously)

[ashlar]

Ok, crossing fingers, I should have solved my problem. I will list what I did, as a reminder to myself and for other users that might find it useful in the future. I have NO idea if the sequence of things I did is relevant or not. Nvidia drivers have bugs, that much is by now obvious to me, it could be random for all I know.

In any case. Starting from the regular, standard EDID after clean driver installation, I did the following.

1. Leave Output Color Depth in Nvidia control panel at default setting (Use default colour settings).
2. Opened CRU, deleted some useless resolutions (useless for me) from CTA-861 extension block. Saved and restarted the video driver (with CRU's restart64.exe). This time it restarted correctly.
3. Imported the settings I wanted for custom resolutions (remember, they used to work before the mishap with black screens upon restart of the video driver). Restarted the video driver. And... wow, it worked!
4. Set Output Color Depth in Nvidia control panel to Use Nvidia Settings. This doesn't change anything, theoretically, but it probably "saves" something somewhere. So you go from 8bit color depth to 8bit color depth. But that's apparently needed.
5. Restarted the machine.
6. Set Output Color Depth at 10bit. Apply. Done.
7. Create a restore point. I actually did it after #3 and redid it after #6.

Points 4 and 5... I tried to do that because I had already reached successfully #3 but when I went straight from "Use default colour settings" to Nvidia settings at 10 bit... it didn't like it. Black screens, need to reboot, etc.

Again, I stress... this is just what I did, no guarantee it's gonna work for anyone else but I thought it was worth reporting...
I now have 10 bit video playback both in Kodi and madVR (with correctly tuned refresh rates) and VRR and HDR are working for games.