I've seen people manage to do this randomly by accident, both on some laptops and even on an eVGA Z390 dark, where they did some combination of something and weren't able to do it again. Whether it's some sort of timing or some key like control/alt/F2 or control alt F1 or control Insert +, or even the left vs right control/alt keys, well if someone knew the exact key combination, it might be posted somewhere. I know for newer MSIbooks, it's left alt, right control, right shift, F2 (may have been F1 on laptop before skylake/6700HQ models).
Did you check win-raid bios mod forums to see if someone knows it?