diff --git a/boot/make-initrd.nix b/boot/make-initrd.nix
deleted file mode 100644
index 3e5133be08b..00000000000
--- a/boot/make-initrd.nix
+++ /dev/null
@@ -1,31 +0,0 @@
-# Create an initial ramdisk containing the closure of the specified
-# file system objects.  An initial ramdisk is used during the initial
-# stages of booting a Linux system.  It is loaded by the boot loader
-# along with the kernel image.  It's supposed to contain everything
-# (such as kernel modules) necessary to allow us to mount the root
-# file system.  Once the root file system is mounted, the `real' boot
-# script can be called.
-#
-# An initrd is really just a gzipped cpio archive.
-#
-# Symlinks are created for each top-level file system object.  E.g.,
-# `contents = {object = ...; symlink = /init;}' is a typical
-# argument.
-
-{stdenv, perl, cpio, contents}:
-
-stdenv.mkDerivation {
-  name = "initrd";
-  builder = ./make-initrd.sh;
-  buildInputs = [perl cpio];
-
-  # !!! should use XML.
-  objects = map (x: x.object) contents;
-  symlinks = map (x: x.symlink) contents;
-  suffices = map (x: if x ? suffix then x.suffix else "none") contents;
-  
-  # For obtaining the closure of `contents'.
-  exportReferencesGraph =
-    map (x: [("closure-" + baseNameOf x.symlink) x.object]) contents;
-  pathsFromGraph = ../helpers/paths-from-graph.pl;
-}
diff --git a/boot/make-initrd.sh b/boot/make-initrd.sh
deleted file mode 100644
index d930e51a03f..00000000000
--- a/boot/make-initrd.sh
+++ /dev/null
@@ -1,39 +0,0 @@
-source $stdenv/setup
-
-set -o pipefail
-
-objects=($objects)
-symlinks=($symlinks)
-suffices=($suffices)
-
-mkdir root
-
-# Needed for splash_helper, which gets run before init.
-mkdir root/dev
-mkdir root/sys
-mkdir root/proc
-
-
-for ((n = 0; n < ${#objects[*]}; n++)); do
-    object=${objects[$n]}
-    symlink=${symlinks[$n]}
-    suffix=${suffices[$n]}
-    if test "$suffix" = none; then suffix=; fi
-
-    mkdir -p $(dirname root/$symlink)
-    ln -s $object$suffix root/$symlink
-done
-
-
-# Get the paths in the closure of `object'.
-storePaths=$(perl $pathsFromGraph closure-*)
-
-
-# Paths in cpio archives *must* be relative, otherwise the kernel
-# won't unpack 'em.
-(cd root && cp -prd --parents $storePaths .)
-
-
-# Put the closure in a gzipped cpio archive.
-ensureDir $out
-(cd root && find * -print0 | cpio -ov -H newc --null | gzip -9 > $out/initrd)
diff --git a/helpers/make-iso9660-image.nix b/helpers/make-iso9660-image.nix
index c4ddfe6bceb..d2ecf5e1a90 100644
--- a/helpers/make-iso9660-image.nix
+++ b/helpers/make-iso9660-image.nix
@@ -48,5 +48,5 @@ stdenv.mkDerivation {
     map (x: [("closure-" + baseNameOf x.object) x.object]) storeContents;
   exportBuildReferencesGraph =
     map (x: [("closure-build-" + baseNameOf x.object) x.object]) buildStoreContents;
-  pathsFromGraph = ./paths-from-graph.pl;
+  pathsFromGraph = ../../nixpkgs/pkgs/build-support/kernel/paths-from-graph.pl;
 }
diff --git a/helpers/modules-closure.nix b/helpers/modules-closure.nix
deleted file mode 100644
index 86015a8b182..00000000000
--- a/helpers/modules-closure.nix
+++ /dev/null
@@ -1,13 +0,0 @@
-# Given a kernel build (with modules in $kernel/lib/modules/VERSION),
-# produce a module tree in $out/lib/modules/VERSION that contains only
-# the modules identified by `rootModules', plus their dependencies.
-# Also generate an appropriate modules.dep.
-
-{stdenv, kernel, rootModules, module_init_tools}:
-
-stdenv.mkDerivation {
-  name = kernel.name + "-shrunk";
-  builder = ./modules-closure.sh;
-  inherit kernel rootModules module_init_tools;
-  allowedReferences = ["out"];
-}
diff --git a/helpers/modules-closure.sh b/helpers/modules-closure.sh
deleted file mode 100644
index d16ff46ecb9..00000000000
--- a/helpers/modules-closure.sh
+++ /dev/null
@@ -1,36 +0,0 @@
-source $stdenv/setup
-
-set -o pipefail
-
-PATH=$module_init_tools/sbin:$PATH
-
-version=$(cd $kernel/lib/modules && ls -d *)
-
-echo "kernel version is $version"
-
-export MODULE_DIR=$kernel/lib/modules/
-
-# Determine the dependencies of each root module.
-closure=
-for module in $rootModules; do
-    echo "root module: $module"
-    deps=$(modprobe --config /dev/null --set-version "$version" --show-depends "$module" \
-        | sed 's/^insmod //')
-    #for i in $deps; do echo $i; done
-    closure="$closure $deps"
-done
-
-echo "closure:"
-ensureDir $out
-for module in $closure; do
-    target=$(echo $module | sed "s^$kernel^$out^")
-    if test -e "$target"; then continue; fi
-    echo $module
-    mkdir -p $(dirname $target)
-    cp $module $target
-    grep "^$module" $kernel/lib/modules/$version/modules.dep \
-        | sed "s^$kernel^$out^g" \
-        >> $out/lib/modules/$version/modules.dep
-    echo $target >> $out/insmod-list
-done
-
diff --git a/helpers/paths-from-graph.pl b/helpers/paths-from-graph.pl
deleted file mode 100644
index 43ce4e68db4..00000000000
--- a/helpers/paths-from-graph.pl
+++ /dev/null
@@ -1,68 +0,0 @@
-use strict;
-use File::Basename;
-
-my %storePaths;
-my %refs;
-
-foreach my $graph (@ARGV) {
-    open GRAPH, "<$graph" or die;
-
-    while (<GRAPH>) {
-        chomp;
-        my $storePath = "$_";
-        $storePaths{$storePath} = 1;
-
-        my $deriver = <GRAPH>; chomp $deriver;
-        my $count = <GRAPH>; chomp $count;
-
-        my @refs = ();
-        for (my $i = 0; $i < $count; ++$i) {
-            my $ref = <GRAPH>; chomp $ref;
-            push @refs, $ref;
-        }
-        $refs{$storePath} = \@refs;
-        
-    }
-    
-    close GRAPH;
-}
-
-
-if ($ENV{"printManifest"} eq "1") {
-    print "version {\n";
-    print "  ManifestVersion: 3\n";
-    print "}\n";
-
-    foreach my $storePath (sort (keys %storePaths)) {
-        my $base = basename $storePath;
-        print "localPath {\n";
-        print "  StorePath: $storePath\n";
-        print "  CopyFrom: /tmp/inst-store/$base\n";
-        print "  References: ";
-        foreach my $ref (@{$refs{$storePath}}) {
-            print "$ref ";
-        }
-        print "\n";
-        print "}\n";
-    }
-}
-
-elsif ($ENV{"printRegistration"} eq "1") {
-    # This is the format used by `nix-store --register-validity
-    # --hash-given' / `nix-store --load-db'.
-    foreach my $storePath (sort (keys %storePaths)) {
-        print "$storePath\n";
-        print "0000000000000000000000000000000000000000000000000000000000000000\n"; # !!! fix
-        print "\n"; # don't care about preserving the deriver
-        print scalar(@{$refs{$storePath}}), "\n";
-        foreach my $ref (@{$refs{$storePath}}) {
-            print "$ref\n";
-        }
-    }
-}
-
-else {
-    foreach my $storePath (sort (keys %storePaths)) {
-        print "$storePath\n";
-    }
-}
diff --git a/installer/default.nix b/installer/default.nix
index 617210f4487..2196890f842 100644
--- a/installer/default.nix
+++ b/installer/default.nix
@@ -19,7 +19,7 @@ in
     inherit nix;
     nixpkgsURL = config.installer.nixpkgsURL;
 
-    pathsFromGraph = ../helpers/paths-from-graph.pl;
+    pathsFromGraph = ../../nixpkgs/pkgs/build-support/kernel/paths-from-graph.pl;
 
     nixClosure = pkgs.runCommand "closure"
       {exportReferencesGraph = ["refs" nix];}
diff --git a/system/system.nix b/system/system.nix
index 87792041295..24806222772 100644
--- a/system/system.nix
+++ b/system/system.nix
@@ -41,8 +41,7 @@ rec {
 
 
   # Determine the set of modules that we need to mount the root FS.
-  modulesClosure = import ../helpers/modules-closure.nix {
-    inherit (pkgs) stdenv module_init_tools;
+  modulesClosure = pkgs.makeModulesClosure {
     inherit rootModules;
     kernel = modulesTree;
   };
@@ -60,9 +59,9 @@ rec {
       lvm2 = if config.boot.initrd.lvm then pkgs.lvm2Static else null;
       allowedReferences = []; # prevent accidents like glibc being included in the initrd
     }
-    "
+    ''
       ensureDir $out/bin
-      if test -n \"$devicemapper\"; then
+      if test -n "$devicemapper"; then
         cp $devicemapper/sbin/dmsetup.static $out/bin/dmsetup
         cp $lvm2/sbin/lvm.static $out/bin/lvm
       fi
@@ -70,7 +69,7 @@ rec {
       cp -p $e2fsprogs/sbin/fsck* $e2fsprogs/sbin/e2fsck $out/bin
       cp $udev/sbin/udevd $udev/sbin/udevtrigger $udev/sbin/udevsettle $out/bin
       nuke-refs $out/bin/*
-    ";
+    '';
   
 
   # The init script of boot stage 1 (loading kernel modules for
@@ -95,17 +94,16 @@ rec {
 
   # The closure of the init script of boot stage 1 is what we put in
   # the initial RAM disk.
-  initialRamdisk = import ../boot/make-initrd.nix {
-    inherit (pkgs) perl stdenv cpio;
+  initialRamdisk = pkgs.makeInitrd {
     contents = [
       { object = bootStage1;
         symlink = "/init";
       }
     ] ++ (if config.boot.initrd.enableSplashScreen then [
-      { object = pkgs.runCommand "splashutils" {} "
+      { object = pkgs.runCommand "splashutils" {} ''
           ensureDir $out/bin
           cp ${pkgs.splashutils}/bin/splash_helper $out/bin
-        ";
+        '';
         suffix = "/bin/splash_helper";
         symlink = "/sbin/splash_helper";
       }