there were some things i ddn't knew about raspberry pis:
"Linux runs on that ARM CPU, we know that, but we might be surprised to learn that Linux on this device is only a second class citizen. The GPU cores run a real time operating system called ThreadX. This operating system is closed source and rules the system without the open source Linux Kernel being aware of it."
https://ownyourbits.com/2019/02/02/whats-wrong-with-the-raspberry-pi/
and guess who bought the ThreadX operating system last april?