Flashing Pixhawk board

Hi, I would like to know if it’s possible to flash Pixhawk flight controller board using Arduino or other ? I would like use the Pixhawk hardware and my own code. I would like to know if it’s possible and how to do that ? Pls don’t start with “why you want to do that ?”, simply useless ! Thank you for your help. Best regards.

The board I use : Pixhawk 4 | PX4 User Guide

Some helpful ressources: