Thank you, @drsensor! I'm impressed by what you have done!

• Is it possible to test it on QEMU? If possible then maybe it can help cross-test Substratum on another platform that supported by QEMU.
  I think it's a great idea and definitely possible. I thought about setting up a QEMU to simulate ARM system so the compiled ARM binaries can be tested. In current tutorial, the test is done only for x64 system.

• Is there any possibility to setup Substratum on OpenWrt? If yes then maybe someone can create a WiFi router that connects directly to Substratum Network
  It must be quite challenging to natively run on OpenWrt. I have to learn more about the hardware and system to see if it's feasible. My intuition is the system resource is highly limited on a router. Again, I'm not familiar of this category. There might be powerful router available for development.

• Seems the installation process of Substratum Node still take a lot of process and time. Maybe creating a Docker image that has many tools necessary for building Substratum Node would help in the long run, including tools to do cross-compilation. Something like this maybe.
  It's actually quite simple and straight forward: cross-compile on a Linux system, and run it on Pi 3 or Zero. I intentionally expanded the multi-step tutorial so even those who have never used Linux or have no Linux system at hand can catch it up, by installing a complete Linux virtual machine on their own computer, setting up a compilation tool-chain, and manually configure and test most of the procedures. I believe people can learn a lot during the process.

  I intentionally avoid providing any binaries, because I believe people should never download any unofficial or unverified binary. As far as I know, SUB team really focuses on making easy-to-use products, such as running Node by one click, which is key for mass adoption. I'm sure the actual installation process will be much easier when Pi is officially supported. It is actually doable now, by creating an automatic installation script, but it may ruin the fun of the whole process :)

  Docker is a great idea. Currently I'm not very familiar with it. I suppose there are available images for the tool-chain.