nerves_system_rpi3 VS buildroot

Once I understood this, I was able to finish step 2 above by learning how to use Buildroot and creating the kernel and dtb. Steps 3, 4, and 5, I use nerves_system_rpi3 as base and made modifications. This is a difficult part to describe what I did.

I did it few times. It's so much easier nowadays with https://buildroot.org/

If you dig through the rootfs of the K1 it becomes clear that Creality is using buildroot so we should be able to do that ourselves - at least some of us.

An embedded system like Roku doesn't need to "run everything", it just needs to run their "platform", which is probably quite small. It's pretty trivial to assemble your own OS from "off-the-shelf" components. You can use something like buildroot to spin up a new OS in half a day, using only the components you want. You can also use "smaller" components that have far fewer features, meaning less bugs and less updates.

https://github.com/buildroot/buildroot

> I do this for every Windows installation that is used for similar purposes, like embedded machines that has to run a single application, virtual machines, etc.

Have you tried running Linux for these use cases? This sort of thing is an area Linux excels, in my experience.

When you run Windows, you're in for the whole kit and caboodle. Most of the components are proprietary, closed-source black boxes. You can only poke and prod and test and hope things don't break in unexpected ways.

Conversely, Linux can be easy stripped down to a bare bones kernel and a single statically-linked binary. I can run a useful application on top of Linux with the whole system weighing in smaller than bootmgfw.efi.

Something more complex, but still custom, is easily crafted with Buildroot.

https://buildroot.org/

Have a look at the commit history of Linux or buildroot for nice readable commit histories.

Gentoo could teach you more about what is involved in dependency handling and actual ‘construction’ of a Linux system. But Linux From Scratch is a much better teaching tool for learning this, and even things like Buildroot are arguably better than Gentoo for this because they generally force you to care about a lot of the stuff that Gentoo hides away to make the system nicer to use.