FuzzyBabyDucks

I have the same h200 firmware flashed as you do. I managed to resolve the issue, although not as I would like it. It was failing because of an issue with proxmox doing the passthrough to the VM. when launching the VM, It would get a PCI address header failure (which apperently can be ignored), but I had my doubts. I installed ESXi on another drive and stuck that in the machine and eevrything just worked perfectly on my first attempt. Unfortunately, that means I have to migrate some of the other vms to ESXi and will have to use full VMs rather than just the containers. Its unfortunate that I couldnt get proxmox working with it though. Have you updated to the latest version of DSM? I'm kinda worried about that potentially breaking things.

I also have an h200 flashed to IT-Mode and a pass-through from proxmox to Xpenology. However I cannot get it to find the hard drives that are attached. I can see through a serial terminal that it is loading the drivers for it when it boots. Do you have any insight into why this might be the case? What synology device was your loader for? I'm using the synology ds3617xs version.