diff --git a/modules/initrd.nix b/modules/initrd.nix
index f4c66273..f33781e7 100644
--- a/modules/initrd.nix
+++ b/modules/initrd.nix
@@ -1,9 +1,110 @@
-{ config, pkgs, ... }:
+{ config, pkgs, lib, ... }:
 
 let
+  inherit (pkgs)
+    busybox
+    makeInitrd
+    mkExtraUtils
+    runCommandNoCC
+    udev
+  ;
+  inherit (lib) flatten optionals;
+
   device_config = config.mobile.device;
+  device_name = device_config.name;
+
   stage-1 = config.mobile.boot.stage-1;
+
+  mobile-nixos-init = pkgs.pkgsStatic.callPackage ../boot/init {};
+  init = "${mobile-nixos-init}/bin/init";
+
+  contents =
+    (optionals (stage-1 ? contents) (flatten stage-1.contents))
+    ++ [
+      # Populate /bin/sh to stay POSIXLY compliant.
+      # FIXME: Do we care?
+      #{ object = "${extraUtils}/bin/sh"; symlink = "/bin/sh"; }
+
+      # FIXME: udev/udevRules module.
+      { object = udevRules; symlink = "/etc/udev/rules.d"; }
+      { object = init; symlink = "/init"; }
+    ]
+  ;
+
+  udevRules = runCommandNoCC "udev-rules" {
+    allowedReferences = [ extraUtils ];
+    preferLocalBuild = true;
+  } ''
+    mkdir -p $out
+
+    # These 00-env rules are used both by udev to set the environment, and
+    # by our bespoke init.
+    # This makes it a one-stop-shop for preparing the init environment.
+    echo 'ENV{LD_LIBRARY_PATH}="${extraUtils}/lib"' > $out/00-env.rules
+    echo 'ENV{PATH}="${extraUtils}/bin"' >> $out/00-env.rules
+
+    cp -v ${udev}/lib/udev/rules.d/60-cdrom_id.rules $out/
+    cp -v ${udev}/lib/udev/rules.d/60-persistent-storage.rules $out/
+    cp -v ${udev}/lib/udev/rules.d/80-drivers.rules $out/
+    cp -v ${pkgs.lvm2}/lib/udev/rules.d/*.rules $out/
+
+    for i in $out/*.rules; do
+        substituteInPlace $i \
+          --replace ata_id ${extraUtils}/bin/ata_id \
+          --replace scsi_id ${extraUtils}/bin/scsi_id \
+          --replace cdrom_id ${extraUtils}/bin/cdrom_id \
+          --replace ${pkgs.coreutils}/bin/basename ${extraUtils}/bin/basename \
+          --replace ${pkgs.utillinux}/bin/blkid ${extraUtils}/bin/blkid \
+          --replace ${pkgs.lvm2}/sbin ${extraUtils}/bin \
+          --replace ${pkgs.mdadm}/sbin ${extraUtils}/sbin \
+          --replace ${pkgs.bash}/bin/sh ${extraUtils}/bin/sh \
+          --replace ${udev}/bin/udevadm ${extraUtils}/bin/udevadm
+    done
+
+    # Work around a bug in QEMU, which doesn't implement the "READ
+    # DISC INFORMATION" SCSI command:
+    #   https://bugzilla.redhat.com/show_bug.cgi?id=609049
+    # As a result, `cdrom_id' doesn't print
+    # ID_CDROM_MEDIA_TRACK_COUNT_DATA, which in turn prevents the
+    # /dev/disk/by-label symlinks from being created.  We need these
+    # in the NixOS installation CD, so use ID_CDROM_MEDIA in the
+    # corresponding udev rules for now.  This was the behaviour in
+    # udev <= 154.  See also
+    #   http://www.spinics.net/lists/hotplug/msg03935.html
+    substituteInPlace $out/60-persistent-storage.rules \
+      --replace ID_CDROM_MEDIA_TRACK_COUNT_DATA ID_CDROM_MEDIA
+  ''; # */
+
+  extraUtils = mkExtraUtils {
+    name = "${device_name}-extra-utils";
+    packages = [
+      busybox
+    ]
+      ++ optionals (stage-1 ? extraUtils) stage-1.extraUtils
+      ++ [{
+      package = runCommandNoCC "empty" {} "mkdir -p $out";
+      extraCommand =
+        let
+          inherit (pkgs) udev;
+        in
+        ''
+          # Copy udev.
+          copy_bin_and_libs ${udev}/lib/systemd/systemd-udevd
+          copy_bin_and_libs ${udev}/bin/udevadm
+          for BIN in ${udev}/lib/udev/*_id; do
+            copy_bin_and_libs $BIN
+          done
+        ''
+      ;
+    }]
+    ;
+  };
+
+  initrd = makeInitrd {
+    name = "initrd-${device_config.name}";
+    inherit contents;
+  };
 in
-{
-  system.build.initrd = pkgs.callPackage ../systems/initrd.nix { inherit device_config stage-1; };
-}
+  {
+    system.build.initrd = "${initrd}/initrd";
+  }
diff --git a/systems/initrd.nix b/systems/initrd.nix
deleted file mode 100644
index f819a1fc..00000000
--- a/systems/initrd.nix
+++ /dev/null
@@ -1,136 +0,0 @@
-{
-  # Configuration from the configuration system.
-  device_config,
-  stage-1 ? {},
-
-  busybox,
-
-  stdenvNoCC,
-  makeInitrd,
-  writeScript,
-
-  lib,
-  mkExtraUtils,
-
-  # FIXME : udev specifics
-  runCommandNoCC,
-  udev,
-  pkgs
-}:
-
-# FIXME: get the udev specifics out of here.
-# The main issue is how `udevRules` needs a reference to `extraUtils`.
-# This means that `extraUtils` should be a build product of stage-1 in
-# system.build, that we can refer to when required.
-
-let
-  inherit (lib) optionals flatten;
-
-  device_name = device_config.name;
-
-  extraUtils = mkExtraUtils {
-    name = device_name;
-    packages = [
-      busybox
-    ]
-      ++ optionals (stage-1 ? extraUtils) stage-1.extraUtils
-      ++ [{
-      package = runCommandNoCC "empty" {} "mkdir -p $out";
-      extraCommand =
-        let
-          inherit (pkgs) udev;
-        in
-        ''
-          # Copy udev.
-          copy_bin_and_libs ${udev}/lib/systemd/systemd-udevd
-          copy_bin_and_libs ${udev}/bin/udevadm
-          for BIN in ${udev}/lib/udev/*_id; do
-            copy_bin_and_libs $BIN
-          done
-        ''
-      ;
-    }]
-    ;
-  };
-
-  shell = "${extraUtils}/bin/ash";
-
-  udevRules = runCommandNoCC "udev-rules" {
-    allowedReferences = [ extraUtils ];
-    preferLocalBuild = true;
-  } ''
-    mkdir -p $out
-
-    echo 'ENV{LD_LIBRARY_PATH}="${extraUtils}/lib"' > $out/00-env.rules
-
-    cp -v ${udev}/lib/udev/rules.d/60-cdrom_id.rules $out/
-    cp -v ${udev}/lib/udev/rules.d/60-persistent-storage.rules $out/
-    cp -v ${udev}/lib/udev/rules.d/80-drivers.rules $out/
-    cp -v ${pkgs.lvm2}/lib/udev/rules.d/*.rules $out/
-
-    for i in $out/*.rules; do
-        substituteInPlace $i \
-          --replace ata_id ${extraUtils}/bin/ata_id \
-          --replace scsi_id ${extraUtils}/bin/scsi_id \
-          --replace cdrom_id ${extraUtils}/bin/cdrom_id \
-          --replace ${pkgs.coreutils}/bin/basename ${extraUtils}/bin/basename \
-          --replace ${pkgs.utillinux}/bin/blkid ${extraUtils}/bin/blkid \
-          --replace ${pkgs.lvm2}/sbin ${extraUtils}/bin \
-          --replace ${pkgs.mdadm}/sbin ${extraUtils}/sbin \
-          --replace ${pkgs.bash}/bin/sh ${extraUtils}/bin/sh \
-          --replace ${udev}/bin/udevadm ${extraUtils}/bin/udevadm
-    done
-
-    # Work around a bug in QEMU, which doesn't implement the "READ
-    # DISC INFORMATION" SCSI command:
-    #   https://bugzilla.redhat.com/show_bug.cgi?id=609049
-    # As a result, `cdrom_id' doesn't print
-    # ID_CDROM_MEDIA_TRACK_COUNT_DATA, which in turn prevents the
-    # /dev/disk/by-label symlinks from being created.  We need these
-    # in the NixOS installation CD, so use ID_CDROM_MEDIA in the
-    # corresponding udev rules for now.  This was the behaviour in
-    # udev <= 154.  See also
-    #   http://www.spinics.net/lists/hotplug/msg03935.html
-    substituteInPlace $out/60-persistent-storage.rules \
-      --replace ID_CDROM_MEDIA_TRACK_COUNT_DATA ID_CDROM_MEDIA
-  ''; # */
-
-  # Just to keep track of this bit.
-  udevFragment = ''
-    mkdir -p /etc/udev
-
-    ln -sfn ${udevRules} /etc/udev/rules.d
-  '';
-
-  stage1 = writeScript "stage1" ''
-    #!${shell}
-
-    #
-    # Basic necessary environment.
-    #
-    export PATH=${extraUtils}/bin/
-    export LD_LIBRARY_PATH=${extraUtils}/lib
-    mkdir -p /bin
-    ln -sv ${shell} /bin/sh
-
-    # ---- stage-1.init START ----
-    ${udevFragment}
-    ${stage-1.init}
-    # ---- stage-1.init END ----
-  '';
-
-  ramdisk = makeInitrd {
-    contents = [ { object = stage1; symlink = "/init"; } ]
-      ++ flatten stage-1.contents
-    ;
-  };
-in
-stdenvNoCC.mkDerivation {
-  name = "initrd-${device_name}";
-  src = builtins.filterSource (path: type: false) ./.;
-  unpackPhase = "true";
-
-  installPhase =  ''
-    cp ${ramdisk}/initrd $out
-  '';
-}