回答“Little yellow button on logic board - what is it?”Old Post, but commenting for prosperity. EXTREMELY IMPORTANT For this model MacBook it is IMPERATIVE that the battery disconnect button be held for 10s (until the tiny led dies) before removing the track pad flex, else you can kill the logic board. On power back up post repair it is IMPERATIVE that the MacBook be connected to a standard USB charger (5v 0.5-1a) until it powers on before connecting to the standard MacBook charger. This is to wake up the power management circuit. Connecting directly to a standard charger after having disconnected the battery can likewise permanently damage the logic board.