diff --git a/pkgs/tools/package-management/nix/unstable.nix b/pkgs/tools/package-management/nix/unstable.nix
index d66a156c33e4..dfbde642f3f2 100644
--- a/pkgs/tools/package-management/nix/unstable.nix
+++ b/pkgs/tools/package-management/nix/unstable.nix
@@ -5,11 +5,11 @@
 }:
 
 stdenv.mkDerivation rec {
-  name = "nix-1.5.2pre3091_772b709";
+  name = "nix-1.5.3pre3134_5c06e52";
 
   src = fetchurl {
-    url = "http://hydra.nixos.org/build/4796316/download/5/${name}.tar.xz";
-    sha256 = "f1acf131842d9604d886d5f98aaa4739bea63536023d7287ce48613c38d49fbd";
+    url = "http://hydra.nixos.org/build/5265350/download/5/${name}.tar.xz";
+    sha256 = "82fd6aad66a8646d923a9a65b04879ea5e320391f047549c88ab7d913e5d5903";
   };
 
   nativeBuildInputs = [ perl pkgconfig ];
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 87ec359af78a..c0f95e08e62a 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -9229,13 +9229,10 @@ let
     stateDir = config.nix.stateDir or "/nix/var";
   };
 
-  nixUnstable = nixStable;
-  /*
   nixUnstable = callPackage ../tools/package-management/nix/unstable.nix {
     storeDir = config.nix.storeDir or "/nix/store";
     stateDir = config.nix.stateDir or "/nix/var";
   };
-  */
 
   nut = callPackage ../applications/misc/nut { };