So I have the 32-bit version of RetroArch latest APK on my Shield TV. Any recommendations for version of MAME I should be using and the most compatible rom pack? I am using 2015 with the latest 0.220 rom pack but having some issues with certain games and wondering if it’s related. Not sure with something as old as Defender why it would be having issues with the coin and start but wondering if it’s related and need to pick a specific version of MAME or some other emulator if suggested and a specific rom set?
for arcade games I use “Final Burn Neo” core and related “FBA” roms
You want the MAME version to be as close to the ROM set version. You are using a 2015 MAME version using a ROM set from this year. That’s 5 years worth of changes, that means a big number of games won’t work. Either get a more recent version of MAME or an older ROM set.