Here I see several images, some for BananaPI BPI SBCs.
But I'm not sure which one is suitable for -M3 or how to make them compatible.
I tried the OMV_4_Banana_Pi.img.xz but it does not boot at all.
By the way there's another download: OMV_4_Banana_Pi_Pro.img.xz, but I cannot find it in the official product list