Believe it or not I've never tried flashing JESC on a 4-in-1 to enable the free 48kHz PWM frequency setting for the ESC/motor communication. Especially on micros this is meant to result in smoother, cooler motors, lower amp draw, and best of all, longer flight times. After trying it I can attest to this with a roughly 20% improvement in flight times. Very happy with this upgrade:)
This won't necessarily make your quad fly better but it will make the motors' job a little easier. More detailed explanations can be found in the links below.
UAV Tech's video:)