Resolving Blocked Battery Issues for Elios 3 Drones with 2025.03 firmware

Since the release of the Elios 3 firmware package 2025.03, we have noted an increase in customer reports of blocked batteries. These batteries exhibit a magenta status LED and fail to communicate with the drone.

To address this, we released a drone firmware hotfix, version 2025.03.1, on October 22nd. This hotfix prevents the battery firmware update, identified as the cause of the issue. We highly recommend updating your drone to this latest version.

Note that the issue is not the battery firmware itself, but is due to the update process.

For customers with already blocked batteries, we also offer a method to revert them to a functional state, see below.

How to revert blocked batteries

To recover blocked Elios 3 batteries showing a magenta status LED, you’ll temporarily downgrade the drone firmware to restore the batteries. Then update both the batteries and the drone to the latest hotfix version (2025.03.1) to prevent the issue from recurring.

The process is described hereunder :

Preparation

1. Download or locate Elios 3 drone firmware files, those files are downloaded by Inspector and stored at %localappdata%/Flyability/Inspector/firmwares. If you don't find them, please find links for each of them :

   1. 2024.07.1.swu

   2. 2025.02.swu

   3. 2025.03.1.swu

Downgrading the drone firmware

1. Ensure you are running the latest version of Inspector (25.3.0.56)

2. Power on your drone and connect it to your computer

3. Ignore any message inviting you to update the drone, click on the Later button

4. From the Inspector Drone menu, click on Flash custom firmware

5. A file selection dialogue will show, navigate to the location of the 2024.07.1.swu file and select it. The downgrade process will start

6. Wait until the drone fully downgrades and reboots

7. When the drone reboots, you will hear a beep, this beep confirms the battery has been flashed with a former battery firmware

Recovering the batteries

1. For each battery displaying the magenta status LED, do the following :

   1. Power off the drone

   2. Place a magenta status LED battery in the drone

   3. Power on the drone

   4. When you hear the beep, the battery should be good again, power off, remove the battery and check its status LED. If the LED is still magenta, try once more.

Upgrading the batteries

While you can proceed with updating the drone to the hotfix version directly, we highly recommend you do an additional step, which will bring the batteries to their latest stable firmware version 1.4.

1. Power on your drone and connect it to your computer

2. Ignore any message inviting you to update the drone, click on the Later button

3. From Inspector Drone menu, click on Flash custom firmware

4. A file selection dialogue will show, navigate to the location of the 2025.02.swu file and select it. The upgrade process will start

5. Wait until the drone fully downgrades and reboots

6. When the drone reboots, you will hear a beep, this beep confirms the battery has been flashed with the battery firmware 1.4

7. Follow the Recovering the batteries process to update all your batteries

Final drone upgrade

1. Power on your drone and connect it to your computer

2. Ignore any message inviting you to update the drone, click on the Later button

3. From Inspector Drone menu, verify that under "ELIOS 3", Inspector suggests updating your drone to 2025.03.1. If it's the case, proceed with the update by clicking on Update now, if not, proceed to step 4

4. From Inspector Drone menu, click on Flash custom firmware

5. A file selection dialogue will show, navigate to the location of the 2025.03.1.swu file and select it. The upgrade process will start

6. Wait until the drone fully downgrades and reboot

Your Elios 3 and batteries are now fully operational again and running the latest version