My Zenith Extreme refuses to boot when I populate 2 Samsung 960 Pro NVMe M.2's onto the board. Using 1 M.2 I have no issues booting into the OS, however when installing a second M.2 all hell breaks loose. It should be noted, that when I first purchased the board I had 1 M.2 installed and never experienced issues. It is only recently when I decided to upgrade my storage with another M.2 that the problems began.

I disconnected all drives except for 1 M.2 installed on the DIMM.2 riser board. Installing Win 10 went smoothly and my system presented no problems booting to my desktop. I then installed the 2nd M.2 directly to the board. The system did recognize the drive and did boot into my desktop. I then formatted the drive and rebooted the system and it never made it back into the OS. I then had the Samsung M.2's tested thinking they might be faulty and both passed testing. I used PC Doctor to test system hardware - all passed. I then used Memtest to test the ram - all passed.

Additionally, if I have both M.2 drives installed, when installing Windows I can see both drives. When I select the drive to install the OS to, it will make it to approximately 20% and fail the install... repeatedly. Remove 1 M.2, Windows installs. I have changed CSM from UEFI to Legacy. Turned off Fast Boot and turned on.
reinstalled UEFI default keys and upgraded to the latest Bios (1402), and still no luck! This certainly has me stumped. I am currently in contact with ASUS service support and have attempted some of the fixes they have suggested and I still cannot install more than 1 M.2 at a time. I am beginning to think the board may need RMA'd? Unless someone can offer other suggestions that might help me get my system up and running with more than 1 M.2 installed! I'm a bit desperate!