The libretro core uses RETRO_PIXEL_FORMAT_RGB565, which can't represent greys, instead of RETRO_PIXEL_FORMAT_0RGB1555 or RETRO_PIXEL_FORMAT_XRGB8888. This causes the libretro core to have a magenta tint (due to the LSB of green always being clear in mGBA's specific RGB565 conversion). I assume this is done for compatibility with some very old specific devices but it has the cost of degrading the image quality for the rest of the targets.
The libretro core uses
RETRO_PIXEL_FORMAT_RGB565, which can't represent greys, instead ofRETRO_PIXEL_FORMAT_0RGB1555orRETRO_PIXEL_FORMAT_XRGB8888. This causes the libretro core to have a magenta tint (due to the LSB of green always being clear in mGBA's specific RGB565 conversion). I assume this is done for compatibility with some very old specific devices but it has the cost of degrading the image quality for the rest of the targets.