my copy of pokemon silver cartridge shipped with a bad save battery. i'd only be able to get to the fourth gym or so before the batteries in my gameboy would die.
Soldered Battery to a Gameboy Advance Game PCB so it can save, it still does not want to save. | TechPowerUp Forums
CR1616 Battery Holder for Game Boy Advance (GBA) Cartridges (Set of 3) – Cool Spot Gaming