How to change safely storage controller mode from RST to AHCI in Windows 10?

windows-10 bios ssd ahci intel-rst

I'd like to answer your second question by saying that your fourth point is valid, since I've just switched a brand new Dell XPS 9310 from RST to AHCI without losing anything (AFAIKT :))
So:

  1. Boot into Windows
  2. Open a shell as administrator
  3. Run bcdedit /set safeboot minimal
  4. Reboot, enter BIOS and switch to AHCI
  5. Reboot into Windows again
  6. Open another shell as administrator
  7. Run bcdedit /deletevalue safeboot
  8. Reboot

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