Its just the debian build service using target=base arch=arm64 with the radxa repo’s and packages.
Plus OMV ontop of that with no customisation so essentially its the radxa image with just a bit of work for OMV already done.
https://wiki.radxa.com/Rockpi4/dev/Debian
Just forgot to enable sudo systemctl enable resize-helper.service so it runs on first boot and disables itself again.
If there are any module needs or probs post as aiming at an OMV install myself so will run through again if anything is missing.