@Efi yeppums, you do. also certain iso images only work with certain bios (luckily they're usually edge cases) and also the images have to be in *.bin and *.cue formats
@Nine but pbp
@Efi okay so, I take it you're using retropie or are you doing this through another thing? Either way for Retropie's Libretro cores, each has a set series of bios images that work with it that need to be in the bios folder. it took some tweaking for mine to work on my Rpi 3b as I had to find just the right images and even then, certain games are... finnicky and I had to find the right image (god, just getting Wipeout 3 Special Edition as an image that worked was a NIGHTMARE)