AlexVS

Thanks for your help, the OMV7 installation went smoothly.

Just checked and it seems like their Release file on the repo is still marked with ovm6 while the package you get when installing is omv7.

Tried to build an image with omv pre-installed, but throw a bunch of errors, so no idea if it works. https://fi.mirror.armbian.de/.testing/Armbian-unofficial_25.02.0-trunk_Rockpro64_bookworm_current_6.12.9-omv.img.xz

If not grab a standard rockpro image ( https://dl.armbian.com/rockpro64/Bookworm_current_minimal ) and proceed according omv docs:  https://docs.openmediavault.org/en/stable/installation/on_debian.html
Keep in mind that omv heavily messes with the system, so if anything breaks after installation (like network access or even boot) we cannot help. This is userspace.
 

Thank you very much. Installed the specified image. OMV has started. Now you can test it. 
 

@AlexVS

Try this:
https://dl.armbian.com/rpi4b/Bookworm_current_minimal-omv