XPS 13 7390 2-in-1 AHCI mode not available

Hello everyone.

I've extensively been trying to set the SATA Operation value in my XPS 7390 to AHCI in order to install Linux on it. The problem I'm constantly having is that every time I save the changes to the BIOS, it reverts back to RAID On.

I tried several combinations in the BIOS, setting AHCI while also:

• Disabling SafeBoot
• Disabling TPM
• Setting Fastboot to Minimal, also to Thorough
• Disabling BIOS Recovery from Hard Wipe
• Performing a Start Data Wipe

I also tried:

• Restoring the Windows OS.
• Changing Windows into Safe Mode before doing the change in the BIOS.
• Resetting the BIOS config to Factory Settings.
• Setting the EmbSataRaid value using fwupd from a Linux liveboot (see below)

[nixos@nixos:~]$ sudo fwupdmgr get-bios-settings |  grep -A9 EmbSataRaidEmbSataRaid:Setting type: EnumerationCurrent Value: RaidDescription: SATA OperationRead Only: FalsePossible Values:0: Disabled1: Ahci2: Raid[nixos@nixos:~]$ sudo fwupdmgr set-bios-setting EmbSataRaid AhciWARNING: UEFI ESP partition not detected or configuredSee https://github.com/fwupd/fwupd/wiki/PluginFlag:esp-not-found for more information.Authenticating… [ - ]Set BIOS setting 'EmbSataRaid' using 'Ahci'.An update requires a reboot to complete. Restart now? [y|N]:

I'm lost on how to proceed here. Is there anything I'm missing?