Game Boy Color Replacement Buttons Flexible PCB
Allow you to repair corroded buttons on Game Boy Color Motherboard

Use for listed Corroded Buttons :

NOTE:
Make sure to do Continuity Test with an Multimeter and "Buzzer" (Beep) function.
Check if all soldered point are having good contact (Multimeter should "Beep").
If on your Motherboard some of welding points are too much corroded and couldn't be used (P00, P01, P02...), 
Then you can use additional soldering points to tied WIRES to the VIAS (see pictures).