Niklas that’s cool!
I’ve said it elsewhere but I’ll say it again, Niklas’ step by step instructions here https://www.sound-machines.it/forums/topic/what-if-i-want-the-original-firmware-back/ made my setup work, and made it possible for me to compile and upload sketches successfully. I am grateful for that. Anyone who is scratching their heads should go there first.
And, just a reminder… the arduino part of the NS1 is optional! You can just plain ignore it if you feel like it! It’s up to you.