# Installing Secure Firmware

Securing firmware involves signing both the bootloader and firmware using the ECC Prime256v1 keypair. The keypair’s private key is securely generated and stored on CubePilot's server. Once a signed bootloader is installed, only firmware signed with an authorized public-private key pair can run on the autopilot. Any unsigned firmware will be blocked from being loaded.

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Failure to follow the secure firmware installation steps could result in the hardware malfunctioning.
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To install the secure bootloader, complete the following steps:

1. Ensure the ArduPilot firmware build environment is installed using Linux or Windows WSL. For details, refer to the following website: [https://ardupilot.org/dev/docs/building-the-code.html](https://ardupilot.org/dev/docs/building-the-code.html#building-the-code)
2. Ensure the latest MAVProxy has been installed. For details, refer to the following website: <https://ardupilot.org/mavproxy/docs/getting_started/download_and_installation.html#mavproxy-downloadinstall>
3. Create a branch to develop the firmware locally.
4. Open Mission Planner.
5. Click **Setup** -> **Secure**.
6. Click **Generate Key** to create a public-private key pair.

<figure><img src="https://3175993181-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LUhw7cdLeWVORgnTA3i%2Fuploads%2Fq6aK87pUWmrqYfaNVslz%2FScreenshot%202024-11-15%20095105.png?alt=media&#x26;token=17e317f4-4b75-4820-b460-f66d1cb58a61" alt=""><figcaption></figcaption></figure>

7. Build a securely signed bootloader for the autopilot via the instructions in the following link: <https://github.com/ArduPilot/ardupilot/tree/master/Tools/scripts/signing>

<figure><img src="https://3175993181-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LUhw7cdLeWVORgnTA3i%2Fuploads%2FWPTHZ0LNMU4E5KdTZIXo%2FScreenshot%202024-11-04%20165831.png?alt=media&#x26;token=179dab88-e3dd-4ba0-9247-cb71e174c435" alt="" width="563"><figcaption></figcaption></figure>

8. Build a securely signed firmware and load it onto the autopilot via the instructions in the following link: <https://github.com/ArduPilot/ardupilot/tree/master/Tools/scripts/signing>

<figure><img src="https://3175993181-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LUhw7cdLeWVORgnTA3i%2Fuploads%2FkW1PokTwfum2u6AWEg3X%2FScreenshot%202024-11-04%20165629.png?alt=media&#x26;token=a980c75a-8db1-4435-920c-a4e94cb01c27" alt="" width="563"><figcaption></figcaption></figure>

9. Use MAVProxy to flash the securely signed bootloader as the new bootloader.
10. Verify that the new secure bootloader has been installed.

For more details, refer to the following link: <https://ardupilot.org/dev/docs/secure-firmware.html>