So, I basically had a Pokemon Emerald cartridge, I was using a CR 2025 battery, I originally did this with Pokemon Ruby and had no problems, I had my Pokemon Emerald cartridge's battery dead, so I replaced it, on the first attempt, I didn't screw in the screw and booted the game, it worked but
Gameboy Advance SP Battery Pack, 850mAh Replacement Rechargeable Lithium-ion Battery + Tool Pack Kit Compatible with Nintendo GBA SP $10.99 $ 10 . 99 Get it as soon as Wednesday, Oct 4Gameboy Advance SP Battery Pack, 850mAh Replacement Rechargeable Lithium-ion Battery + Tool Pack Kit Compatible with Nintendo GBA SP 4.6 out of 5 stars 322 $10.99 $ 10 . 99I have a gba sp and the battery is good, however the contact is creating a similar issue. the battery can still hold a charge very close to what is in the wikipedia page (8+ hours) the thing is, i need to snap the power button in a specific "clean" way otherwise it will show red while the battery is more than half full.