diff --git a/pkgs/default.nix b/pkgs/default.nix
index 216318b..e9b536d 100644
--- a/pkgs/default.nix
+++ b/pkgs/default.nix
@@ -38,14 +38,6 @@ let
       inherit revstring diskName;
     };
 
-  disk-script-fn =
-    { moduleIds ? null
-    ,
-    }:
-    pkgs.callPackage ./disk-script {
-      bundle = bundle-fn { inherit moduleIds; };
-    };
-
 in
 rec {
   default = moduleit;
@@ -66,11 +58,15 @@ rec {
   # For prod use: builds the Nixmodules disk image
   bundle-image-tarball = pkgs.callPackage ./bundle-image-tarball { inherit bundle-image revstring; };
 
-  disk-script-dev = disk-script-fn {
-    moduleIds = dev-module-ids;
+  disk-script = pkgs.callPackage ./disk-script {
+    bundle = bundle-fn { };
   };
 
-  disk-script = disk-script-fn { };
+  disk-script-dev = pkgs.callPackage ./disk-script-dev {
+    bundle = bundle-fn {
+      moduleIds = dev-module-ids;
+    };
+  };
 
   # For dev use: builds the shared Nixmodules disk
   bundle-squashfs = bundle-squashfs-fn {
diff --git a/pkgs/disk-script-dev/default.nix b/pkgs/disk-script-dev/default.nix
new file mode 100644
index 0000000..11507ba
--- /dev/null
+++ b/pkgs/disk-script-dev/default.nix
@@ -0,0 +1,47 @@
+{ writeShellApplication
+, bundle
+, squashfsTools
+, coreutils
+, findutils
+, closureInfo
+,
+}:
+
+let
+  diskClosureInfo = closureInfo { rootPaths = [ bundle ]; };
+in
+writeShellApplication {
+  name = "disk-script";
+  runtimeInputs = [
+    coreutils
+    findutils
+    squashfsTools
+  ];
+  text = ''
+    set -x
+    TMP_DIR=$(mktemp -d)
+
+    cd "$TMP_DIR"
+
+    root="$TMP_DIR/root"
+    diskImage="$TMP_DIR/disk.sqsh"
+
+    (
+        mkdir -p "$root/nix/store" "$root/etc/nixmodules"
+
+        cp --archive --reflink=auto "${bundle}/etc/nixmodules/"* "$root/etc/nixmodules"
+
+        SECONDS=0
+        xargs -P "$(nproc)" cp -a --reflink=auto -t "$root/nix/store/" < "${diskClosureInfo}/store-paths"
+        echo "xargs copy took $SECONDS seconds" >&2
+
+        echo "making squashfs..."
+        SECONDS=0
+        mksquashfs "$root" "$diskImage" -force-uid 11000 -force-gid 11000 -comp lz4 -b 1M
+        echo "mksquashfs took $SECONDS seconds" >&2
+
+    ) 1>&2
+
+    echo "$diskImage"
+  '';
+}
diff --git a/pkgs/disk-script/default.nix b/pkgs/disk-script/default.nix
index 61f9969..1c7ec1d 100644
--- a/pkgs/disk-script/default.nix
+++ b/pkgs/disk-script/default.nix
@@ -30,7 +30,8 @@ writeShellApplication {
     cd "$TMP_DIR"
 
     root="$TMP_DIR/root"
-    diskImage="$TMP_DIR/disk.sqsh"
+    # gcp requires that disks end in "disk.raw"
+    diskImage="$TMP_DIR/disk.raw"
     tarball="$TMP_DIR/disk.sqsh.tar.gz"
 
     (
@@ -48,7 +49,7 @@ writeShellApplication {
         echo "mksquashfs took $SECONDS seconds" >&2
 
         SECONDS=0
-        tar --use-compress-program="pigz --best --recursive | pv" -Scf "$tarball" disk.sqsh 
+        tar --use-compress-program="pigz --best --recursive | pv" -Scf "$tarball" "$diskImage"
         echo "tar took $SECONDS seconds" >&2
 
         echo Tarball created at "$tarball" >&2