diff --git a/pkgs/tools/package-management/nix/unstable.nix b/pkgs/tools/package-management/nix/unstable.nix
index 30d0b8f345eb..51bcb9ef298a 100644
--- a/pkgs/tools/package-management/nix/unstable.nix
+++ b/pkgs/tools/package-management/nix/unstable.nix
@@ -3,14 +3,14 @@
 , stateDir ? "/nix/var"
 }:
 
-let version = "0.11pre9718"; in
+let version = "0.12pre10069"; in
 
 stdenv.mkDerivation {
   name = "nix-${version}";
   
   src = fetchurl {
     url = "http://nix.cs.uu.nl/dist/nix/nix-${version}/nix-${version}.tar.bz2";
-    md5 = "cae130dcc51a30eff34fc194e17891f2";
+    md5 = "bf05ebe9463f0453beae2c43f05ac13d";
   };
 
   buildInputs = [perl curl openssl];
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 0c455514b94f..499b78ea9cf0 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -4936,15 +4936,11 @@ rec {
   };
 
   # The bleeding edge.
-  /*
   nixUnstable = import ../tools/package-management/nix/unstable.nix {
     inherit fetchurl stdenv perl curl bzip2 openssl;
     aterm = aterm242fixes;
     db4 = db45;
   };
-  */
-
-  nixUnstable = nix;
 
   nixCustomFun = src: preConfigure: configureFlags :
   (import ../tools/package-management/nix/custom.nix {