Hello,

Before found the great Synology_HDD_db-project, I was hassling with the system. The Linux system did recognize the nvme device, so did:
sudo mkfs.ext4 /dev/nvme0n1
sudo mkdir -p /volumeSSD
sudo mount /dev/nvme0n1 /volumeSSD

Also set support_disk_compatibility="no" and support_m2_pool="yes"

So I got a volume that can be used in SSH, read and write, but not existing in the Synology UI. Then I did found the project and tried few options, lastly:
syno_hdd_db.sh -fpin

Currently:
sudo syno_hdd_util --ssd_detect --> not in the list
sudo synonvme --get-location /dev/nvme0 --> Can't get the location of /dev/nvme0
sudo synonvme --is-nvme-ssd /dev/nvme0 --> It is a NVMe SSD
sudo synonvme --m2-card-model-get /dev/nvme0 --> Not M.2 adapter card
sudo synonvme --model-get /dev/nvme0 --> Model name: WD Red SN700 500GB

sudo nvme list
Node SN Model Namespace Usage Format FW Rev

/dev/nvme0n1 25035L800770 WD Red SN700 500GB 1 500.11 GB / 500.11 GB 512 B + 0 B 111150WD

udevadm info /dev/nvme0
P: /devices/pci0000:00/0000:00:01.1/0000:01:00.0/nvme/nvme0
N: nvme0
E: DEVNAME=/dev/nvme0
E: DEVPATH=/devices/pci0000:00/0000:00:01.1/0000:01:00.0/nvme/nvme0
E: MAJOR=250
E: MINOR=0
E: PHYSDEVBUS=pci
E: PHYSDEVDRIVER=nvme
E: PHYSDEVPATH=/devices/pci0000:00/0000:00:01.1/0000:01:00.0
E: SUBSYSTEM=nvme
E: SYNO_INFO_PLATFORM_NAME=v1000
E: SYNO_KERNEL_VERSION=4.4
E: SYNO_SUPPORT_USB_PRINTER=yes
E: SYNO_SUPPORT_XA=no
E: USEC_INITIALIZED=995487

cat /etc.defaults/extensionPorts
[pci]
pci1="0000:00:01.1"

sudo smartctl -a /dev/nvme0 --> Read NVMe Identify Controller failed: NVMe Status 0x400b

Fan is running full speed, probably because no temperature information from the NVMe Controller.

Rebooted, yes. Next try - "shut down to cold and plug off the power cord", but not until finished ongoing file copy. Not feeling so lucky, so asking already. Expecting lack of own knowledge about these systems. Update needs arise when Btrtfs was causing problems under 30 million files..

I'm not really sure if the system should even should work with Startech x4 PCI Express adapter. It seems to work at least partially at the moment.

Cheers, Kimmo