u/dairymarkly

Hey everyone,
I’m using RetroArch on iOS with the mGBA core to play Pokémon (GBA ROM / ROM hack), and I noticed a thin white line running vertically along the right edge of the screen during gameplay.

EDIT: SOLVED!
Thank you everyone.
I found the issue—it was caused by the Video Filter set to 2xSaI.
If anyone else runs into this on iOS RetroArch:

1. Go to Settings > Video > Video Filter.
2. Turn off 2xSaI or switch it to a different filter.
   Once I changed it, the white line along the edge completely disappeared!
   (Maybe 2xSaI is an old pixel-upscaling algorithm that calculates pixels based on their neighbors. When processing the far right column of the game screen, it has no "right neighbor" to sample from, causing it to render a default white/blank line at the edge boundary.)