Main LED
Flashing red and blue: Initializing gyroscopes. !! Hold the vehicle still and level while it initializes the sensors.
Flashing blue: Disarmed, no GPS lock found. Autopilot, loiter, and return-to-launch modes require GPS lock.
Solid blue: Armed with no GPS lock
Flashing green: Disarmed (ready to arm), GPS lock acquired. Quick double tone when disarming from the armed state.
Solid green-with single long tone at time of arming: Armed, GPS lock acquired. Ready to fly!
Double flashing yellow: Failing pre-arm checks (system refuses to arm).
Single Flashing yellow: Radio failsafe activated
Flashing yellow-with quick beeping tone: Battery failsafe activated
Flashing yellow and blue-with high-high-high-low tone sequence (dah-dah-dah-doh): GPS glitch or GPS failsafe
activated
Flashing red and yellow-with rising tone: EKF or Inertial Nav failure
Flashing purple and yellow: Barometer glitch
Solid Red: Error
Solid Red with SOS tone sequence: SD Card missing (or other SD error like bad format etc.)
FMU PWR: Green-Power LED-Always On
FMU B/E :
Yellow-Error indicator
Fast Blink: Bootloader Active (the blue LED should be off in this state)
Blinking: CPU is too heavily loaded.
OFF: System OK
IO PWR : Green-Power LED-Always On
IO B/E :
Yellow-Error indicator
Fast Blink: Bootloader Active (the blue LED should be off in this state)
4Hz: No FMU Input (e.g. no controller app loaded at startup)
ON: Initialization error, check your RC config options in your parameters
OFF: System OK
ACT: Blue-Heartbeat(심장박동) LED
2Hz Blink-Heartbeat Loop Running
Solid-Uploading new firmware for IO (red LED should be solid or blinking unevenly)
Safety Switch
ON: FMU and IO ARMED
Slow Blink: Ready to arm
Fast Blink: Error / refusing to arm
Long Off with fast double blink: IO armed, but FMU not
Long Off with fast quad blink: FMU armed, but IO not