Reverse engineer a firmware file

Job ID: 31044767

Budget: $30 – $250 USD

I have a firmware file and I would like to update a constant. The firmware file, which runs on a GoPro HERO9 Black, can be found here: https://bit.ly/35JJlcc or alternatively downloaded from: https://community.gopro.com/t5/en/Introducing-GoPro-Labs/ta-p/603173

The constant I am looking to update is called `maximum_bitrate`, which I would like to update to be 8Mbps. I would also like documentation on how to mount the underlying filesystem so I can make additional changes in the future. Also, I suspect the firmware may be integrity protected, so please update the integrity check if it is present and include documentation on how that was done as well. As far as I can tell, the firmware is neither encrypted nor compressed.
Related categories: C Programming C++ Programming Firmware