How could you do a clean system reset after someone had access to all installed software/data including the cryptographic keys? The information is gone, maybe the recovery partition is changed. How could you securely recover?

I'm freelancer and helped to develop some head units. I have a surprize for you: This documentation mostly doesn't exsists. Most of the time there are some chip datasheets and requirement documents, depending on the customer(car manufacturer) they are good or bad and then are some partly outdated wiki pages written down for some important special things. You learn all other stuff out of the code or from your colleagues.

Wait two years and the most knowledge is gone, except of the things that are used for the next head unit.

In my opinion this auther don't know what he wants.

When my life would depend on this, I would NEVER accept to only have a complex electronic device keeping me alive when I dont understand it and can't repair it in the dark with my swiss army knife. It's a really honest text, but the anger and helplessness is just self implied. It's crazy how people today are so unable to manage their life without electronics.

So yes, all things that I accepted first I hate now. The others I was born in, can't tell much about them. Maybe the people are right but accept the shit later.