diff --git a/corepkgs/Makefile.am b/corepkgs/Makefile.am
index 94d3735723..729d15e7b1 100644
--- a/corepkgs/Makefile.am
+++ b/corepkgs/Makefile.am
@@ -1,6 +1,6 @@
 all-local: config.nix
 
-files = nar.nix buildenv.nix buildenv.pl unpack-channel.nix unpack-channel.sh derivation.nix fetchurl.nix fetchurl.sh
+files = nar.nix buildenv.nix buildenv.pl unpack-channel.nix unpack-channel.sh derivation.nix fetchurl.nix
 
 install-exec-local:
 	$(INSTALL) -d $(DESTDIR)$(datadir)/nix/corepkgs
diff --git a/corepkgs/fetchurl.nix b/corepkgs/fetchurl.nix
index 29cf6720b3..8fc1c5970b 100644
--- a/corepkgs/fetchurl.nix
+++ b/corepkgs/fetchurl.nix
@@ -5,13 +5,20 @@ with import <nix/config.nix>;
 assert (outputHash != "" && outputHashAlgo != "")
     || md5 != "" || sha1 != "" || sha256 != "";
 
+let
+
+  builder = builtins.toFile "fetchurl.sh"
+    ''
+      echo "downloading $url into $out"
+      ${curl} --fail --location --max-redirs 20 "$url" > "$out"
+    '';
+
+in
+    
 derivation {
   name = baseNameOf (toString url);
   builder = shell;
-  args = [ "-e" ./fetchurl.sh ];
-
-  # Compatibility with Nix <= 0.7.
-  id = md5;
+  args = [ "-e" builder ];
 
   # New-style output content requirements.
   outputHashAlgo = if outputHashAlgo != "" then outputHashAlgo else
@@ -19,7 +26,7 @@ derivation {
   outputHash = if outputHash != "" then outputHash else
       if sha256 != "" then sha256 else if sha1 != "" then sha1 else md5;
   
-  inherit system url curl;
+  inherit system url;
 
   # No need to double the amount of network traffic
   preferLocalBuild = true;
diff --git a/corepkgs/fetchurl.sh b/corepkgs/fetchurl.sh
deleted file mode 100644
index 6d35794caf..0000000000
--- a/corepkgs/fetchurl.sh
+++ /dev/null
@@ -1,3 +0,0 @@
-echo "downloading $url into $out"
-
-$curl --fail --location --max-redirs 20 "$url" > "$out"