@RunningSnakes @JuanMena Thank you very much for the detailed response!
First thing I've deleted my old Retroarch 1.8.9 app and settings folder from the SD since it was messy anyway.
After that I've picked up the "
retroarch-wii" folder from "
MAME2003-WII-0.4\apps\" (Wiimpathy V4 core file) and put it on SD.
I've tried OutRun with core D and it works!
Now I want to better understand the whole thing about not being able to see other cores after selecting a game.
I've saw the JuanMena post about modifying the .info files but I don't know where to pick those files in the first place.
I've found this other tutorial:
Retroarch Wiiflow Plugins: independent cores and pixel perfect scanlines
the file you download on point 2 has a lot more files and by going into this folder:
Retroarch Wii - independent cores and pixel perfect scanlines\Retroarch-Wii\info\
I've find a bunch of info files, one of them was "
mame2003_plus_libretro.info", so I've put that one into my SD:
SD:\apps\retroarch-wii\info\
Then copied it multiple times and changed the namefiles of them by matching Wiimpathy cores and then changing the inside info as well with a matching "display_name" but it didn't worked, Retroarch still see one core when you load a rom, I've must missed something :'D
Since I failed with this, right now I load the appropriate core before and then when loading the rom, the only Mame 2003 core shown is the one I've already loaded and the game work.
I would love to properly run this tho.
Then there is WiiFlow Lite, which I never used before and yesterday I've tried to mess up with it and I've failed as well. I've tried following that "
Retroarch Wiiflow Plugins" guide I've posted before and ended up with this (wanted to test just core D since I don't have much space left on SD):
But nothing happened when I've clicked on the "plugin" button on the WiiFlow app, so I'm lost. I've picked this version btw:
https://github.com/Fledge68/WiiFlow_Lite/releases/tag/v5.5.3
Thank you again for the previous help and thank you for any extra help you are willing to give me, I really appreciate it :'D