Is the GCode generated on RPi0 and then send to Farmduino express board or it is generated on web interface and then send to RPi0?
GCode is a private implementation detail that never travels over the network (it stays between the Arduino and RPi). The web app uses higher level abstractions.
Here are the parts of the codebase that handle GCode:
Additionally, you will need a good understanding of the Elixir programming language and tools:
My ability to help end users set up development eenvironments is limited.
it is not possible to use RPi0 to install there the OS for comminication over serial (USB) with Genesisv1.2 right?
With the current version of FBOS, this is correct. We assume that if you are on an RPi0, you are only using a Farmduino board. I want to update FBOS to allow Express users to upgrade their RPi from a Pi zero to a Pi3, but it took longer than expected and I had to stop in order to work on higher priority issues.