Thanks @tkaiser for your quick reply.
My bad, I though it was M2* (for all M2 devices). Guess, I'm gonna have to read twice about a board before buying it (especially about the SATA connector). For anyone else in my position, I used an old stretch Armbian image (5.59), with armbian-config to install OMV4.
As @tkaiser said in another thread, I will probably switch to an ODROID, and keep the M2Berry for another project (firewall maybe?!)
Thanks again,
Bob