Quick answer! Not the one I was hoping for, but at least I can stop trying now! Weird as I have seen videos of it running in the Retroflag case from a year or more back, guessing it was unstable and removed? Thanks anyway, appreciate it.
@tdelios Just a single file per MAME version/folder, a lot less annoying than changing the core for every single game using the UI menus.
And no, there is no plan to split MAME into version.
Recalbox is currently supporting AdvanceMame, MAME2000, 2003, 2003+, 2010 and 2015 (maybe more in the future). It would be even more confusing than having a single folder.