"Several in-service reports have been received from operators that the auto-throttle remained engaged in the IDLE mode when the flight crew advanced the thrust levers to conduct a balked landing. Once airborne, the thrust levers moved back to idle."
Isnt this is what caused the 777 accident at Dubai...
once there is weight on wheels, the ac is in LAND mode, therefore the autothrottles will not advance thrust, even when pressing TOGA.