This is a know issue on some Skylake models from Asus and other vendors, the bios contains the AMI NVMe driver and no mods are needed.
The main culprit here on this subject is the OEM system board hw design/slot electrical connection circuit that doesnt support PCIe NVMe drives, only PCIe AHCI SATA disks.
This is no subject for a mod as fix and im not aware of anything related with success.