@Haemogoblin said in RetroPie is v4.1 RPI2b advice:
I'm just looking in to how to direct Retropie to use one single rom directory for both emulators.
The /home/pi/RetroPie/roms/arcade/ directory was made for this use case. And then you have to define what arcade emulator to use when launching a game in runcommand menu (you just need to set this once).
edit: this post seems to have some useful info for you: https://retropie.org.uk/forum/topic/5674/solved-rom-version-numbers-to-match-emulators