I’ve been doing it manually for the past two days on FBA. Here’s what I do.
– Launch the game and try it out using PiFBA. If it doesn’t work, I launch the game again using the libretro FBA emulator. If it works, I leave the libretro FBA as the default emulator for that game. If it doesn’t work…
– …on the game selection screen I press Select on my controller (CTRL key on keyboard, if I remember correctly) and look at the rom file name, then I delete that rom using my laptop which is connected through my network to my Pi. Then I move on to the next game.
– There are also some games that have a bunch of associated roms. For example, in PiFBA, you might see several entries on the game select menu for Final Fight. One of those is the main rom while the others are different language/region versions. What I do, then, is find the rom that plays the language/region I want and delete the rest, EXCEPT for the main rom. That way you end up with two roms of the same name on your game menu.
– You can keep your menu like that, but I go a step further: on the game select screen, go to the main rom for the game and press Select on your controller and change that game name. What I do is change it from Final Fight to zz– Final Fight –zz. That way that rom will show up last in your list. You still have the language/region you selected as the Final Fight rom.
Lots of work, I know, but I couldn’t come up with a better solution.