CSM disabled goes back to enable

[oli.mathieu]

With OpenCore it is recommended to have CSM disable in the BIOS
I noticed that my USBMap.kext isn't working with CSM enable

My issue is the CSM goes back to enable at some reboot. And when it's enable, it never goes bas to disable.
What can change the status on the CSM in the BIOS ?
I read PS2 keyboard and very old USB peripheral could do that. but I havent any of those
Have you other any idea ?
Thanks in advance

 

[Edhawk]

1. Which system is this happening on?
2. CSM being reset to Enabled, is usually caused by an older GPU not having UEFI drivers, so the system reverts to the Legacy setup for CSM.
3. While it is recommended that CSM be disabled, it doesn't have to be if the system is using older components.
4. Do you have Secure Boot disabled, along with the secure keys?
5. Do you have the OS set as Other OS or Windows8/10?

Have you tried using the 'default/recommended' bios settings, and then changing everything to suit booting macOS?

 

[oli.mathieu]

1. Which system is this happening on?

AsRock X299 Fatality Gaming I9 | i9-7920X | RX 6800 XT

1. CSM being reset to Enabled, is usually caused by an older GPU not having UEFI drivers, so the system reverts to the Legacy setup for CSM.

Okay. I have a BlackMagicDesign Decklink mini monitor PCIe Card......

1. While it is recommended that CSM be disabled, it doesn't have to be if the system is using older components.

I don't think I'm using older components : SATA SSD & HDD with one NVME

1. Do you have Secure Boot disabled, along with the secure keys?

Yes

1. Do you have the OS set as Other OS or Windows8/10?

With CSM Disabled you don't have option to choose the OS

Have you tried using the 'default/recommended' bios settings, and then changing everything to suit booting macOS?

Yes ... unfortunately

When I do so there is several boots (not always the same number) before CSM becomes enabled. The hardware stays the same !!

Thanks for your help. much appreciate