I have been searching for a related issue that I am having when trying to calibrate the compass and have not had any luck. I have no problem going into compass calibration mode, I rotate horizontally until I get the solid green lights and then turn it nose down to rotate it vertically. This is where the problem starts. After rotating 360°, I get rapid flashing red lights that do not stop. I have to turn off and back on the phantom to start again. This happens each time I try to calibrate the compass. My firmware is updated to the latest 3.12, I am in Naza mode and have tried advanced IMU calibration. Please help.