Mame core for Hummingboard and "insert coin" button sometimes doesn't work...

Hey guys, I’ve finally got Lakka working on my Hummingboard. Anyways, some games don’t let me “insert a coin”, while others let me insert one via the SELECT button (I have a SFC30 controller). Maybe it’s a problem with Final Burn Alpha, so I tried to load the mame core, but there doesn’t seem to be a mame core available for arm boards. Is there a way to add one? Thanks in advance McCarthy