I tried to config the buttons through the main input config area while retropie was running and found that retropie recognizes the Ultimate OI board by Ultimarc as one game controller. Seems to me it has to be configured through the script manually. I'm trying it tonight to see if I'm successful. Did you ever get yours working @EspenT ?

Thanks.

I solved this as detailed here: (you have to save a keymap and set the active keymap to "positional (user)")...

https://retropie.org.uk/forum/topic/25350/c64-vice-not-saving-hotkeys?_=1586028149192

@caver01 i'm unable to test either but if mame2010 does something different i could look into it, but i would have thought it wouldn't be respecting the api if it did anything different!