I built a small project using a Raspberry Pi Zero. Wanted to use it in my car. One frustration is that it takes 30+ seconds to boot and show signs of life on power-on.
Wondering how much faster I can make this, or a Pico? Before I lose all the benefits of Linux.
You want to take a look at buildroot-based approaches. They're not quite instant-on, but they're tolerable. https://github.com/showmewebcam/showmewebcam is a good example.