I have a WS C422 Sage/10G motherboard which supports two M.2 slots. I got 2x Inland Premium 1TB SSD 3D NAND M.2 2280 PCIe NVMe 3.0 x4 Internal Solid State Drives to go into those slots. According to the motherboard specification, both M.2 slots support 2280 type drives, so I assumed both would be compatible. I installed the drives into the two slots on the motherboard, one of which is an upright slot, and the other is a flat slot with a standoff.
However, when I live boot the workstation (use Arch Linux Live CD) and give the
fdisk -l command, it is only showing one of the drives as
/dev/nvme0n1. The other drive is not listed.
I suspect it may be a hardware problem, because when I go into the BIOS, the list of boot devices only has one "PCIe SSD" listed, not two.
I have SATA set to ACHI (the default) in the BIOS.
How can I further diagnose this problem?