Cloned M.2 SSD Won't boot

I have a system built on AsusP6X58D-E motherboard. I installed my WD 512 GB NVMe M.2 hard drive on an ACon/Able PCI-e 1xM.2 PCIE = 2x M.2 SATA SSD Low Profile PCIe 3.0 x4 Host Adapter located in a PCI-e slot (last on the board). The original drive is a OCZ 256 REVODRIVE3x2 SCSI Disk located in PCI-e slot 2. I know that I have a PCI-e 2.0 and not 3.0 slots.

I cloned my Win7 hard drive using Easus Todo Backup Home 10.6. I get a good clone. It is recognized in Disk Managment as "Healthy (Active, Primary Partition). I find the Microsoft driver in Device Manager under Storage Controllers as Standard MVN Express Controller as version 6.1.7601.18615 and trying to update am told that this is the latest version. Under Drives I find: NVMe WDC WES512G1X0C-SCSI Disk Device with latest driver version: 6.1.7600.16385.
The drive is recognized in Windows Explorer as Drive A: with the name of the original boot drive.

On reboot the Bios dosn’t find the drive

When I reboot and go to Bios or a Boot menu the drive is not recognized (does not appear in either). I presume that this is due to the inablility of the Bios. Anyone know of a workaround or is this not possible. Seems OCZ has done it.
Any help would be appreciated.

NVMe drives do not use the same drivers as SATA drives so cloning form one to the other probably would not work.

Also NVMe drives do not work as boot drives under legacy BIOS. To use a NVMe drive as a boot drive you must have UEFI.

I would suggest checking the MB and see if it supports UEFI. If it does set it to UEFI not BIOS and do a full install of the OS. Windows 10 is best as Windows 7 does not have native driver support for booting from NVMe drives.

Here are a few knowledge base articles from the WD support site that may help.

I installed the latest NVMe drivers on the old system prior to cloning. They were released by Microsoft as KB2990941 and KB3087873. So I know that the Win7 NVMe drivers are correct. As far as I can tell the Bios does not support UEFI. I am able to use the drive as a storage drive only at this point. If anyone knows of a work around for the NON UEFI Bios let me know.
Thanks