Bpi-m3 on HDMI to eDP LCD converter


I want to use the Bpi-m3 via hdmi cable that leads to an eDP LCD converter. I tho do get no Image at all. The screen stays dark. Tried it with the actual Ubuntu Image on sd and the Android one on emmc. Both are working on my TV like a charm. The converter is the one used in the selfmade pi-top laptop that works with the rpi 3 without problems.

Do you have an idea or hint for me what I can do? Any idea appreciated.

Thanks and greetings, Ent