In general there's a duplicate entry resulting in 'apt update' warning:
Currently testing with RockPro64 using ayufan's latest OMV4 armhf image and running in a similar issue with duplicate entries:
Code
W: Target Packages (main/binary-armhf/Packages) is configured multiple times in /etc/apt/sources.list.d/omv.list:1 and /etc/apt/sources.list.d/openmediavault.list:1
So I would assume this is part of the generic OMV installation routine since both his and mine images are 100% scripted/automated. It's the 'deb http://packages.openmediavault.org/public/ arrakis main' line that is a duplicate. No idea which file to delete in this case