yes I am using debian. I can also bring my mod at work to try with windows 10 if it helps.
Yes I kept the button pressed during power up and for a few seconds.
And I am based in France. But I am OK to follow instructions to try to fix it before shipping it back (I am working in electronics, and I designed an embedded linux device some years ago… I am not afraid by command line, or by opening the case if a cable needs to be connected directly on PCB).