1 files changed, 13 insertions, 4 deletions
diff --git a/lass/1systems/blue/source.nix b/lass/1systems/blue/source.nix
index 8f748ab8f..a52771a4d 100644
--- a/lass/1systems/blue/source.nix
+++ b/lass/1systems/blue/source.nix
@@ -1,11 +1,20 @@
 { lib, pkgs, ... }:
 {
   nixpkgs = lib.mkForce {
-    file = toString (pkgs.fetchFromGitHub {
-      owner = "nixos";
-      repo = "nixpkgs";
+    derivation = let
       rev = (lib.importJSON ../../../krebs/nixpkgs.json).rev;
       sha256 = (lib.importJSON ../../../krebs/nixpkgs.json).sha256;
-    });
+    in ''
+      with import (builtins.fetchTarball {
+        url = "https://github.com/nixos/nixpkgs/archive/${rev}.tar.gz";
+        sha256 = "${sha256}";
+      }) {};
+      pkgs.fetchFromGitHub {
+        owner = "nixos";
+        repo = "nixpkgs";
+        rev = "${rev}";
+        sha256 = "${sha256}";
+      }
+    '';
   };
 }