Firmware upload from QgroundControl

Hii everyone,

Where can I get the code flow or what data QGCS transmit via USB in order to upload a firmware?

From git:

Thanks for the reply. But I mean to ask what commands qgcs sends in order to upload the firmware.
What are those commands like for uploading a mission we’re sending first count then acknowledgement after that individual waypoints etc. Similarly for uploading firmware, what is the protocol?