SATA Mode on Erazer P15609

[if_it_rains]

I've been trying to switch the SATA mode on an Erazer P15609 gaming laptop from Intel RST to AHCI. I'm trying to do this to install Linux on a new NVMe SSD that I have installed alongside the original. The problem I run into is that every time I set the SATA mode to AHCI, the SATA mode revers to Intel RST. Specifically the following occurs:

1 - Set SATA Mode to AHCI in BIOS/UEFI.

2 - Save changes and exit.

3 - Machine immediately reboots.
4 - Return to BIOS/UEFI to find SATA Mode is set to Intel RST.

I've tried the following to get around this:

* Disabling Secure Boot.

* Running Windows in safe mode.

* Disabling Windows Boot Manager.

* Setting a Supervisor Password.

* Setting a User Password.

Nothing I've tried seems to make the SATA mode persisit through a reboot. I'm honestly stumped on this one. If anyone has had any experience with his, and potentially a fix, please let me know.

On a side note, if there's a firmware update for this machine available, I cannot find it. The BIOS details are:
Version: 1.07.08RME5_00011

KBC/EC Version: 1.07.01

ME FW Version: 12.0.47.1524

If an update could fix the problem, is there a link to it?

[if_it_rains · Accepted solution]

I managed to fix my own issue... Had a hunt around the German side of this forum and found a this post BIOS speichert "SATA Mode: AHCI Mode" nur für den nächsten start which describes almost the exact issue I was having. Though there is a critical difference in the solution. The solution described in that post will not work. Microsoft has been migrating functionality away from the older Command Prompt / msconfig utilities. Apparently Windows 11 is completely disabling them but they've been buggy and poorly maintained for years. You must use the Windows Update section of the Settings app. You're looking for "Optional updates" as shown:

I couldn't tell you which of these updates fixed it. The dated ones predate me purchasing this machine in September 2020. Either way the BIOS version is now updated to "1.07.08RME8" and that has fixed the issue entirely.

Just documenting this for the sake of posterity. Thanks to @fischer_1248 and @Andi for their previous solution the problem. 👍