Thanks! It turned out the old approach wasn’t working for a lot of people. Some forgot to uncomment ExecStart, some did uncomment two statements and didn’t understand what’s going. We’ll add more notes in the future and possibly integrate the frame config in the emlidtool.
Okay, these are valid points! We’ll add more notes how to pass more options to ArduPilot. You’ve figured out how to do it, haven’t you, though? So I guess this was pretty easy to understand! 
Good idea! I’ll see to it.
This is actually what we had in mind in the first place. update-alternatives is just a robust and clear way to update links to binaries.
Guys, thanks for your very valuable input!