NixOs module override

configuration.nix

{ config, pkgs, ... }:

{
  disabledModules = [
    "services/audio/roon-server.nix"
  ];
  
  imports = [
    ./roon-server-pinned.nix
  ];
  
  ...
}

roon-server-pinned.nix

args@{config, lib, pkgs, ...}:
let
  pin = builtins.fetchTarball {
    name = "nixos-2020-08-25";
    url = "https://github.com/nixos/nixpkgs/archive/28945790d05bf78ae7979d68736b657736d9370e.tar.gz";
    sha256 = "101m5zj4cr3g6slpda4m6k9yqbxf1gmdy6h1jpfbf47yrq2zs86n";
  };
  unstable = import pin { config = { allowUnfree = true; }; };
in
(import (pin + "/nixos/modules/services/audio/roon-server.nix") ({
  pkgs = unstable;
} // (removeAttrs args ["pkgs"])))