Bought a used drone from a friend. I have calibrated the compass and my tablet says GPS mode is good. All lights are green on TX. The front 2 lights on the craft are solid red. Everything I can find refers to a needed firmware upgrade. However, my tablet says that the most current firmware is loaded. I didn't notice the solid reds until I was airborne. Craft was flying perfectly and landed with no issues. I'm new so don't assume I know anything.