From my understanding of laws in Germany, in Germany, you're allowed to do all of this if your goal is interoperability of systems. If your goal is to not pay them money - which you strategically unwisely hinted at with this question - then that's not covered by that exemption, I think. So from my understanding, adding new music and releasing the tooling for that should be fine, but IANAL. Frankly, what is or isn't l…
And because software vendors never provide a Linux version of their stuff, you kinda have to do it anyways, because you end up with a hardware piece you can’t use without.