Rechargeable battery mod for the Game Boy Advance console.
Slight modification required to the battery compartment, please see photos.
USB-A to USB-C compatible
Like other similar mods you will need to cut a slot for the USB-C charger port in the battery cover to charge without removing the cover.
Battery cover can be used without cutting a hole as long as you don't mind removing the cover to charge.
Red + Blue light= Charging
Red = Fully charged