@@ -13,11 +13,18 @@ options = "--delete-older-than 30d";
     };
   };
 
+  nixpkgs.config = {
+    packageOverrides = pkgs: {
+      unstable = import <nixos-unstable> {
+        config = config.nixpkgs.config;
+      };
+    };
+  };
+
   system.autoUpgrade = {
     enable = true;
   };
   systemd.services.nixos-upgrade = {
-    environment.NIXPKGS_ALLOW_UNFREE = "1";
     script = ''
       ${config.system.build.nixos-rebuild}/bin/nixos-rebuild boot ${toString config.system.autoUpgrade.flags}
     '';

@@ -1,10 +1,6 @@
 { config, pkgs, ... }:
 
-let
-  pkgsUnstable = import <nixos-unstable> {};
-  # pkgsUnstable = pkgs;
-in
-{ environment.systemPackages = with pkgsUnstable; [
+{ environment.systemPackages = with pkgs.unstable; [
     nodejs-8_x
     phantomjs2
     nodePackages.yarn

@@ -1,9 +1,5 @@
 { config, pkgs, lib, ... }:
 
-let
-  pkgsUnstable = import <nixos-unstable> {};
-  # pkgsUnstable = pkgs;
-in
 { virtualisation = {
     docker = {
       enable = true;
@@ -23,7 +19,7 @@ google-chrome
     docker_compose
     electrum
     robomongo
-    pkgsUnstable.slack
+    unstable.slack
   ];
 
   services.mongodb = {

@@ -1,11 +1,9 @@
 { config, pkgs, lib, ... }:
 
 let
-  pkgsUnstable = import <nixos-unstable> {};
-  # pkgsUnstable = pkgs;
   emacsPackage = import ../packages/emacs.nix {
     inherit (pkgs) stdenv;
-    pkgs = pkgsUnstable;
+    pkgs = pkgs.unstable;
     emacs = pkgs.lib.overrideDerivation (pkgs.emacs.override {
         withGTK2 = false;
         withGTK3 = true;