Cube Orange status LED's

I’m just trying to find out what the green and orange (amber) colored LED lights mean on the Cube itself without the GPS or external RGB LED indicator connected. It will flash orange really fast when I first connect a battery or plug in via USB, then they stay on solid with ornage and green after it powers up. Are these status lights of some kind? If so, what do they mean?

May I know what firmware you used on your cube?

Copter 4.3.4. Official in Mission Planner

You can not use the LED on side of your Cube to check your FC state like GPS LED .