diff --git a/pkgs/applications/networking/browsers/chromium/default.nix b/pkgs/applications/networking/browsers/chromium/default.nix
index 889c2ad8318..4c3a02dcecc 100644
--- a/pkgs/applications/networking/browsers/chromium/default.nix
+++ b/pkgs/applications/networking/browsers/chromium/default.nix
@@ -1,5 +1,8 @@
 { stdenv, getConfig, fetchurl, makeWrapper, which
 
+# this is needed in order to build the versions older than 21.x
+, subversion
+
 # default dependencies
 , bzip2, flac, speex
 , libevent, expat, libjpeg
@@ -26,6 +29,7 @@ let
   mkConfigurable = stdenv.lib.mapAttrs (flag: default: getConfig ["chromium" flag] default);
 
   config = mkConfigurable {
+    channel = "stable";
     selinux = false;
     nacl = false;
     openssl = true;
@@ -36,7 +40,7 @@ let
     pulseaudio = getConfig ["pulseaudio"] true;
   };
 
-  sourceInfo = import ./source.nix;
+  sourceInfo = builtins.getAttr config.channel (import ./sources.nix);
 
   mkGypFlags = with stdenv.lib; let
     sanitize = value:
@@ -69,12 +73,14 @@ let
     use_system_v8 = false;
   };
 
+  needsSubversion = stdenv.lib.versionOlder sourceInfo.version "21.0.0.0";
+
   defaultDependencies = [
     bzip2 flac speex
     libevent expat libjpeg
     libpng libxml2 libxslt
     xdg_utils yasm zlib
-  ];
+  ] ++ stdenv.lib.optional needsSubversion subversion;
 
 in stdenv.mkDerivation rec {
   name = "${packageName}-${version}";
diff --git a/pkgs/applications/networking/browsers/chromium/source.nix b/pkgs/applications/networking/browsers/chromium/source.nix
deleted file mode 100644
index 2dc94ea2943..00000000000
--- a/pkgs/applications/networking/browsers/chromium/source.nix
+++ /dev/null
@@ -1,5 +0,0 @@
-{
-  version = "21.0.1179.1";
-  url = "http://commondatastorage.googleapis.com/chromium-browser-official/chromium-21.0.1179.1.tar.bz2";
-  sha256 = "1ynm1dv8nwjg6a0absid1g3r62y0mpb74pmal8g9nmqb92rlkdnc";
-}
diff --git a/pkgs/applications/networking/browsers/chromium/sources.nix b/pkgs/applications/networking/browsers/chromium/sources.nix
new file mode 100644
index 00000000000..db07bc460c7
--- /dev/null
+++ b/pkgs/applications/networking/browsers/chromium/sources.nix
@@ -0,0 +1,19 @@
+# This file is autogenerated from update.sh in the same directory.
+# VHASH: 5e5af2017fa2e05f11aa741c6f87fff0549b93e3bc2aa40e6cc0a0aff84ba010
+{
+  dev = {
+    version = "21.0.1180.15";
+    url = "http://commondatastorage.googleapis.com/chromium-browser-official/chromium-21.0.1180.15.tar.bz2";
+    sha256 = "0ahsrsyw4928vg1kl3dv44q77ksp85crw6m7fy20nq46qihb0mxa";
+  };
+  beta = {
+    version = "20.0.1132.47";
+    url = "http://commondatastorage.googleapis.com/chromium-browser-official/chromium-20.0.1132.47.tar.bz2";
+    sha256 = "1rd1lfn9xchf4nrgi46van5aigqxj2n303890sslc4bcj6p8fkm3";
+  };
+  stable = {
+    version = "20.0.1132.47";
+    url = "http://commondatastorage.googleapis.com/chromium-browser-official/chromium-20.0.1132.47.tar.bz2";
+    sha256 = "1rd1lfn9xchf4nrgi46van5aigqxj2n303890sslc4bcj6p8fkm3";
+  };
+}
diff --git a/pkgs/applications/networking/browsers/chromium/update.sh b/pkgs/applications/networking/browsers/chromium/update.sh
index 066cd1c147f..c9dd69df9a2 100755
--- a/pkgs/applications/networking/browsers/chromium/update.sh
+++ b/pkgs/applications/networking/browsers/chromium/update.sh
@@ -1,34 +1,50 @@
 #!/bin/sh
 
+channels_url="http://omahaproxy.appspot.com/";
 bucket_url="http://commondatastorage.googleapis.com/chromium-browser-official/";
+output_file="$(cd "$(dirname "$0")" && pwd)/sources.nix";
 
-get_newest_version()
+get_channels()
 {
-    curl -s "$bucket_url" | sed -ne ' H;/<[Kk][Ee][Yy]>chromium-[^<]*</h;${
-    g;s/^.*<Key>chromium-\([^<.]\+\(\.[^<.]\+\)\+\)\.tar\.bz2<.*$/\1/p
-    }';
+    for chline in $(echo "$1" | cut -d, -f-2);
+    do
+        channel="${chline%%,*}";
+        version="${chline##*,}";
+
+        url="${bucket_url%/}/chromium-$version.tar.bz2";
+
+        sha256="$(nix-prefetch-url "$url")";
+
+        echo "  $channel = {";
+        echo "    version = \"$version\";";
+        echo "    url = \"$url\";";
+        echo "    sha256 = \"$sha256\";";
+        echo "  };";
+    done;
 }
 
 cd "$(dirname "$0")";
 
-version="$(get_newest_version)";
+versions="$(curl -s "$channels_url" | sed -n -e 's/^linux,\(\([^,]\+,\)\{2\}\).*$/\1/p')";
 
-if [ -e source.nix ]; then
-    oldver="$(sed -n 's/^ *version *= *"\([^"]\+\)".*$/\1/p' source.nix)";
-    if [ "x$oldver" = "x$version" ]; then
-        echo "Already the newest version: $version" >&2;
+if [ -e "$output_file" ];
+then
+    vhash="$(echo "$versions" | sha256sum | cut -d' ' -f1)";
+    old_vhash="$(sed -n 's/# *VHASH: *//p' "$output_file")";
+
+    if [ "x$vhash" = "x$old_vhash" ];
+    then
+        echo "$output_file is already up to date, bailing out." >&2;
         exit 1;
     fi;
 fi;
 
-url="${bucket_url%/}/chromium-$version.tar.bz2";
+channels="$(get_channels "$versions")";
 
-sha256="$(nix-prefetch-url "$url")";
-
-cat > source.nix <<EOF
+cat > "$output_file" <<-EOF
+# This file is autogenerated from update.sh in the same directory.
+# VHASH: $vhash
 {
-  version = "$version";
-  url = "$url";
-  sha256 = "$sha256";
+$channels
 }
 EOF