Hi Andreas,
I also don’t know anything about kernels or even patching them. However, it seems like it’s possible to patch the kernel given the existence of the nonguix channel of packages – though I might be mistaken.
If I’m correct in my assumptions we could initiate a “reform” guix channel that has all reform-specific versions of things that we need, including a patched version of the libre kernel if that’s possible.
One sticky issue will be discussing this with actual Guix people in their own forums. There is a policy of not recommending or really discussing non-free software in those places. For us this is kind of unavoidable due to the few exceptions in the Reform system. I imagine, however, that we can get most of the way there.