Astro SB003 – Emergency Disarm bug in Astro firmware v1.0.21

Date Released: June 22nd, 2022
Subject: Emergency Disarm bug in Astro firmware v1.0.21
Effectivity: Effective immediately
Required Action: Update Astro aircraft and Herelink controller to firmware version 1.1.11 immediately before next flight or take mitigation actions to set correct parameters on firmware version 1.0.21


This Service Bulletin is being issued to alert all Astro operators that Freefly has found a software bug in Astro firmware version 1.0.21 that affects the emergency stop function in Auterion Mission Control (v1.021 was launched with the Astro Base units). This bug is fixed in firmware version 1.1.11.


The Freefly Astro running Auterion Mission Control (AMC) on the Ground Control Station has a feature where the user can activate an emergency stop action at any time- this disarms the motors in the event of an out-of-control aircraft (activating this in air will result in a crash).

It was found in internal testing that aircraft running firmware 1.0.21 may experience motors going to maximum throttle for 3 seconds if emergency stop mechanism is used. The root cause of this issue is a code failure setting the failsafe PWM values on the IO processor.

In the failure scenario, if the user selects emergency kill in AMC and then confirms via swipe, the motors go to full power for 3 seconds before the batteries return to hotswap mode and fault, shutting down the drone.

The correct behavior should be: If the user selects emergency kill in AMC and then confirms via swipe, the motors would shut off and the aircraft disarms.


The issue has been resolved in Astro firmware 1.1.11 which is already released. Users are strongly encouraged to update firmware on both the Astro aircraft and Herelink controller immediately. Note: The Herelink Ground Control Station must get firmware updated in order to work with new Astro firmware 1.1.11

In the specific cases where users can’t update and must continue flying on 1.0.21, the following work around should be used- Configure the following parameters as specified:

  • PWM_MAIN_FAIL1 = 900
  • PWM_MAIN_FAIL2 = 900
  • PWM_MAIN_FAIL3 = 900
  • PWM_MAIN_FAIL4 = 900

These parameters would need to be reapplied if the drone parameters are reset. Updating 1.1.11 is the preferred solution.

How to download firmware:

  • Directions on how to update Astro firmware and the Herelink controller firmware
  • The aircraft firmware version can be downloaded from the Freefly Support page and applied to the Astro using a laptop. The Astro firmware version should be at least v1.1.11
  • The Herelink controller must be updated as well before the Astro can fly on v1.1.11. The Herelink firmware can be downloaded via the Over-the-Air updates when you connect the herelink to wifi. The Herelink firmware version should be at least FFAROU1220425

Where to download firmware:


  1. Do not fly Astro on firmware version 1.0.21
    1. Update all Astros to firmware version 1.1.11 or later immediately and do not fly if aircraft is not updated
    2. Update Herelink controller to version FFAROU1220425 or later (required in conjunction with Astro v1.1.11)

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