Things You'll Need
Instructions
Turn off the power on the GBA and take the game out of the cartridge slot.
Spray compressed air (or blow) into the bottom of the cartridge. Dust or debris may be causing a faulty connection that prevents the game from saving.
Follow the same procedure as Step 2 with the slot inside the GBA. Hold the GBA upside down while you do this so that if dust becomes loosened it will fall out of the game slot.
Run a silk cloth (or a cloth made of any smooth material) along both of the areas that you just sprayed. This will clean out any remaining debris.
Put the game back into the GBA. Turn on the power and attempt to save the game.