I tried to update from 21.05 to unstable, but trying to rebuild the system, I got an error telling me ATI drivers aren’t supported, but I can’t see why they would be brought in since I don’t specify it anywhere. The error comes from here: https://github.com/NixOS/nixpkgs/blob/bcf132c9a7fa586fc16f809fb7af3d5ee1dd13dd/pkgs/top-level/linux-kernels.nix#L513
Backtrace when trying to rebuild:
Break down your config to a minimal reproducer; find out which line causes it.
Then open an issue upstream.