Flipped the arm switch and motors won't spin? Your flight controller tells you why. Below are all Betaflight 4.4 and 4.5 Arming Disable Flags compiled from firmware source: what each means and how to clear it.
NOGYRO4.4 / 4.5
Gyroscope not detected
Bit 1 · Beep code 1 · Source ARMING_DISABLED_NO_GYRO
The flight controller did not detect a gyroscope on boot. Without a gyro the FC cannot stabilize, so arming is blocked.
How to fix- Verify the flashed firmware target matches your exact flight controller model — flashing the wrong target is the most common cause.
- Try reflashing a previously working firmware version.
- If it still fails, the gyro or FC hardware may be damaged; contact support for inspection.
FAILSAFE4.4 / 4.5
Failsafe active
Bit 2 · Beep code 2 · Source ARMING_DISABLED_FAILSAFE
The flight controller is currently in failsafe mode, for example right after losing RC link.
How to fix- Resolve the link-loss cause first (radio, receiver, antennas).
- Wait for RC link recovery and failsafe to clear.
- Turn the arm switch off, then arm again.
RXLOSS4.4 / 4.5
No valid RC signal
Bit 3 · Beep code 3 · Source ARMING_DISABLED_RX_FAILSAFE
The flight controller is not receiving a valid receiver signal.
How to fix- Power on your radio and confirm the receiver is bound (solid status LED).
- Move sticks in the Receiver tab of Betaflight Configurator to verify channel bars respond.
- Check receiver wiring, confirm Serial RX is enabled on the matching UART in Ports, and verify the receiver protocol in Receiver tab.
Official note: if RXLOSS flashes in OSD mid-flight, your link is at the edge — treat it as critical signal loss and fly back immediately.
BADRX4.4 only
Link recovered with arm switch on
Bit 4 · Beep code 4 · Source ARMING_DISABLED_BAD_RX_RECOVERY
The receiver just recovered from signal loss while the arm switch was already ON. The FC locks arming so motors do not spin up unexpectedly.
How to fix- Flip the arm switch back to OFF.
- Flip the arm switch ON again to arm.
Renamed to NOT_DISARMED in Betaflight 4.5 with the same trigger condition.
NOT_DISARMED4.5 only
Link recovered with arm switch on
Bit 4 · Beep code 4 · Source ARMING_DISABLED_NOT_DISARMED
New name for BADRX in 4.5. The receiver regained signal while the arm switch was ON, so the FC blocks arming to prevent sudden motor spin.
How to fix- Flip the arm switch back to OFF.
- Flip the arm switch ON again to arm.
Shares bit 4 with 4.4 BADRX and uses the same underlying check.
BOXFAILSAFE4.4 / 4.5
Failsafe switch is active
Bit 5 · Beep code 5 · Source ARMING_DISABLED_BOXFAILSAFE
You assigned FAILSAFE to an AUX switch in the Modes tab, and that switch is currently active.
How to fix- Flip that switch back to the off position.
- Check which channel and range FAILSAFE is mapped to in the Modes tab to avoid accidental triggers.
RUNAWAY4.4 / 4.5
Runaway takeoff protection triggered
Bit 6 · Beep code 6 · Source ARMING_DISABLED_RUNAWAY_TAKEOFF
Right after arming/takeoff, the FC detected uncontrolled attitude/spin and disarmed automatically. Common causes: motor order/direction, FC orientation, or reversed props.
How to fix- Turn the arm switch OFF to clear this flag.
- Verify motor order and spin direction in the Motors tab, board alignment, and propeller orientation.
- Do not repeatedly force arming until the root cause is fixed.
Controlled by CLI parameter runaway_takeoff_prevention.
CRASH4.4 / 4.5
Crash detected — auto-disarmed
Bit 7 · Beep code 7 · Source ARMING_DISABLED_CRASH_DETECTED
With crash recovery set to DISARM (crash_recovery = DISARM), the FC detected a crash and locked arming.
How to fix- Turn the arm switch OFF to clear this flag.
- Inspect props, motors, and frame for damage before flying again.
THROTTLE4.4 / 4.5
Throttle not at minimum
Bit 8 · Beep code 8 · Source ARMING_DISABLED_THROTTLE
The throttle stick is above minimum, so arming is blocked for safety.
How to fix- Lower the throttle stick all the way down.
- Check the throttle channel value in the Receiver tab — it must be below min_check (default 1050).
- If it cannot reach below min_check, recalibrate gimbals on your radio or adjust throttle endpoints/subtrim.
ANGLE4.4 / 4.5
Quad tilted too far
Bit 9 · Beep code 9 · Source ARMING_DISABLED_ANGLE
The quad is tilted past the small_angle limit (default 25°).
How to fix- Place the quad on a level surface before arming.
- If it still triggers while flat, calibrate the accelerometer in the Setup tab.
- Check Board Alignment settings if the FC is rotated or flipped.
Ignored when Flip Over After Crash (Turtle Mode) is active.
BOOTGRACE4.4 / 4.5
Power-on grace period active
Bit 10 · Beep code 10 · Source ARMING_DISABLED_BOOT_GRACE_TIME
Arming is blocked for a few seconds right after boot (default 5s via pwr_on_arm_grace), and until DShot ESCs are ready.
How to fix- Wait about 5 seconds after plugging in the battery before arming.
- If the arm switch was already ON at power-up, turn it OFF, wait a few seconds, then arm.
NOPREARM4.4 / 4.5
Prearm switch not engaged
Bit 11 · Beep code 11 · Source ARMING_DISABLED_NOPREARM
A PREARM switch is configured in Modes, and it is not active (or was not cycled after the previous disarm).
How to fix- Hold/engage the PREARM switch first, then flip the arm switch.
- Cycle PREARM off and back on after every disarm before re-arming.
LOAD4.4 / 4.5
FC CPU load too high
Bit 12 · Beep code 12 · Source ARMING_DISABLED_LOAD
The flight controller processor is overloaded. 4.4 checks average CPU load; 4.5 checks task-scheduling slip rate.
How to fix- Lower the PID loop frequency one step in the Configuration tab.
- Disable unused features (extra telemetry, LED strip, excessive Blackbox logging rate, etc.).
CALIB4.4 / 4.5
Sensors calibrating
Bit 13 · Beep code 13 · Source ARMING_DISABLED_CALIBRATING
Gyro or other sensors are currently calibrating on boot.
How to fix- Keep the quad completely still on a stable surface for a few seconds.
- If stuck calibrating, move the quad away from vibrations and re-plug the battery.
CLI4.4 / 4.5
CLI mode open
Bit 14 · Beep code 14 · Source ARMING_DISABLED_CLI
The Configurator CLI (Command Line Interface) is currently active.
How to fix- Type exit and press Enter in CLI, or disconnect the Configurator.
CMS4.4 / 4.5
OSD menu (CMS) open
Bit 15 · Beep code 15 · Source ARMING_DISABLED_CMS_MENU
The stick-activated OSD settings menu (CMS) is still open.
How to fix- Select Exit or Save & Exit inside the OSD menu.
BST4.4 / 4.5
Blocked by BST device
Bit 16 · Beep code 16 · Source ARMING_DISABLED_BST
Official docs: a Black Sheep Telemetry device (such as TBS Core Pro) is preventing arming.
How to fix- Follow that device’s manual to clear the lock condition.
Rarely encountered in 4.5; legacy support item.
MSP4.4 / 4.5
Configurator (MSP) connected
Bit 17 · Beep code 17 · Source ARMING_DISABLED_MSP
The FC is connected to Betaflight Configurator via USB/MSP. This is normal whenever plugged into a PC or phone.
How to fix- Click Disconnect in the Configurator or unplug the USB cable.
- Use the Motors tab for bench motor tests — always remove propellers first!
PARALYZE4.4 / 4.5
Paralyze mode triggered
Bit 18 · Beep code 18 · Source ARMING_DISABLED_PARALYZE
PARALYZE mode was triggered by a switch. It permanently locks arming until power cycle even if you flip the switch back.
How to fix- Unplug and re-plug the flight battery to power-cycle the FC.
- Check the Modes tab to make sure PARALYZE is not bound unintentionally.
GPS4.4 / 4.5
Insufficient GPS satellites
Bit 19 · Beep code 19 · Source ARMING_DISABLED_GPS
GPS Rescue is enabled, but GPS has no fix or fewer satellites than gps_rescue_min_sats.
How to fix- Wait outdoors in an open area for GPS lock.
- To test without a lock, enable gps_rescue_allow_arming_without_fix (note: Rescue will not work without a fix).
- Disable GPS Rescue if you do not plan to use it.
RESCUE_SW4.4 / 4.5
GPS Rescue switch is ON
Bit 20 · Beep code 20 · Source ARMING_DISABLED_RESC
The GPS Rescue AUX switch is currently active.
How to fix- Flip the GPS Rescue switch off before arming.
RPMFILTER4.4 only
RPM filter missing ESC telemetry
Bit 21 · Beep code 21 · Source ARMING_DISABLED_RPMFILTER
RPM filtering is enabled, but at least one ESC is not returning bidirectional DShot RPM telemetry.
How to fix- Confirm your ESC firmware supports bidirectional DShot (BLHeli_32, Bluejay, AM32).
- Select DShot300 or DShot600 and enable Bidirectional DShot.
- Check the Motors tab to see which motor has 100% error / missing RPM, then inspect that motor/ESC signal wire.
Replaced by DSHOT_TELEM in Betaflight 4.5.
DSHOT_TELEM4.5 only
Bidirectional DShot telemetry missing
Bit 21 · Beep code 21 · Source ARMING_DISABLED_DSHOT_TELEM
Replacement for RPMFILTER in 4.5: Bidirectional DShot (dshot_bidir) is ON, but a motor is not reporting RPM telemetry.
How to fix- Verify ESC firmware supports bidirectional DShot (BLHeli_32, Bluejay, AM32).
- Check per-motor error rates in the Motors tab to isolate any wiring or ESC issue.
- If your ESCs do not support it, turn off Bidirectional DShot (RPM filter will also turn off).
Shares bit 21 with 4.4 RPMFILTER; 4.5 triggers whenever dshot_bidir is enabled without telemetry.
REBOOT_REQD4.4 / 4.5
Reboot required
Bit 22 · Beep code 22 · Source ARMING_DISABLED_REBOOT_REQUIRED
You changed a setting that requires a flight controller reboot to take effect.
How to fix- Save settings and reboot the FC, or power-cycle the battery.
DSHOT_BBANG4.4 / 4.5
DShot Bitbang failure
Bit 23 · Beep code 23 · Source ARMING_DISABLED_DSHOT_BITBANG
Bitbang DShot motor output failed to initialize, usually due to a timer conflict with another peripheral.
How to fix- In CLI, try set dshot_bitbang = AUTO or OFF, then save.
- Disable features that may share timers (such as LED strip) and retest.
- Verify the flashed firmware target matches your flight controller.
NO_ACC_CAL4.4 / 4.5
Accelerometer not calibrated
Bit 24 · Beep code 24 · Source ARMING_DISABLED_ACC_CALIBRATION
An accelerometer-dependent mode or feature is enabled (Angle/Horizon, GPS Rescue, OSD artificial horizon), but the accelerometer is uncalibrated.
How to fix- Place the quad flat, click Calibrate Accelerometer in the Setup tab, and save.
- Or remove Angle/Horizon/GPS Rescue modes if you fly Acro only.
MOTOR_PROTO4.4 / 4.5
Motor protocol not selected
Bit 25 · Beep code 25 · Source ARMING_DISABLED_MOTOR_PROTOCOL
ESC/Motor protocol in Configuration is still set to DISABLED.
How to fix- Select a motor protocol (usually DShot300 or DShot600) in Configuration, then Save and Reboot.
ARMSWITCH4.4 / 4.5
Arm switch is active
Bit 26 · Beep code 26 · Source ARMING_DISABLED_ARM_SWITCH
The most common flag: the arm switch was already ON at power-up, or stayed ON after a blocked arming attempt. Whenever another flag blocks arming, ARMSWITCH appears alongside it.
How to fix- Flip the arm switch to OFF, then back ON.
- If other flags are present, fix those first and ARMSWITCH will clear automatically.
OSD suppresses ARMSWITCH when other disable reasons are active.
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