Hey! I think I have an answer for most of you. If the battery swap doesn’t works, open your GBA SP up and be assured that the screen ribbon cable is properly and fully plugged in the motherboard - and that the locks on both side of the ribbon port is properly pushed fully down (or up if it’s not plugged in a perpendicular position). Most of the time when I repair a GBA SP with that flickering thing going on, that’s what is happening. Also, it sometimes can create a random restart on your GBA, so it’s kind of a sign that your GBA SP doesn’t receive properly the AC/Power from the battery to the screen.