One of our customers have purchased SSD drives for the NVME port. they set the system to boot to NVME by default, but ~40% of the time they boot into MMC. A few more reboots and a Nano/Nx on our customised carrier board will eventually get to NVME, but they are concerned this indicates a fundamental problem with this mode.
Note they have using this code to change the boot drive:
Can you advise if NVME is supported as the primary boot system? if not what is the best method you suggest?