There is a very simple way to do this, Microsoft has it all laid out.
1) Exit all Windows-based programs.
2) Click Start, type regedit in the Start Search box, and then press ENTER.
3) If you receive the User Account Control dialog box, click Continue.
4) Locate and then click one of the following registry subkeys:
5) In the right pane, right-click Start in the Name column, and then click Modify.
6) In the Value data box, type 0, and then click OK.
7) On the File menu, click Exit to close Registry Editor.
The only one I saw was Msahci with the “name” option, so I changed that from 3 to 0 (hexdceimal), rebooted, and changed BiOS over to AHCI, and I was good to go. Rebooted, and it was live in ahci!