diff --git a/nixos-modules/eris/default.nix b/nixos-modules/eris/default.nix
index 1941c56..1ca028b 100644
--- a/nixos-modules/eris/default.nix
+++ b/nixos-modules/eris/default.nix
@@ -1,9 +1,55 @@
-{ pkgs, ... }: {
-  imports = [ ./rom-fs.nix ./rom-memory.nix ];
+{ config, lib, pkgs, ... }:
 
+{
   genode.core.children.eris_rom = {
     package = pkgs.genodePackages.cached_fs_rom;
     configFile = ./cached_fs_rom.dhall;
   };
 
+  genode.core.children.eris_vfs = {
+    fs = let
+      vfsRump = lib.getEris' "lib" pkgs.genodePackages.rump "vfs_rump.lib.so";
+    in {
+      package = pkgs.genodePackages.vfs;
+      extraErisInputs = [ vfsRump ];
+      configFile = pkgs.writeText "rom-vfs.dhall" ''
+        let Sigil = env:DHALL_SIGIL
+
+        let VFS = Sigil.VFS
+
+        in  ${./rom-vfs.dhall}
+              "${config.block.partitions.store.guid}"
+              Sigil.Init.Resources::{ caps = 256, ram = Sigil.units.MiB 32 }
+              ( VFS.vfs
+                  [ VFS.leafAttrs
+                      "plugin"
+                      (toMap { load = "${vfsRump.cap}", fs = "cd9660", ram = "12M", writeable="no" })
+                  ]
+              )
+      '';
+    };
+    memory = {
+      package = pkgs.genodePackages.vfs;
+      configFile = pkgs.writeText "rom-vfs.dhall" ''
+        let Sigil = env:DHALL_SIGIL
+
+        let VFS = Sigil.VFS
+
+        in  ${./rom-vfs.dhall}
+              "${config.block.partitions.store.guid}"
+              Sigil.Init.Resources::{ ram = Sigil.units.MiB 4 }
+              ( VFS.vfs
+                  [ VFS.leafAttrs
+                      "tar"
+                      ( toMap
+                          { name =
+                              "${config.system.build.tarball}/tarball/${config.system.build.tarball.fileName}.tar"
+                          }
+                      )
+                  ]
+              )
+      '';
+    };
+  }.${config.genode.core.storeBackend};
+
 }
diff --git a/nixos-modules/genode-core.nix b/nixos-modules/genode-core.nix
index 80d3c2b..51995c4 100644
--- a/nixos-modules/genode-core.nix
+++ b/nixos-modules/genode-core.nix
@@ -21,9 +21,9 @@ let
 
   bootConfigFile = let
 
-    storeBackendInputs = {
-      memory = [ config.system.build.tarball ];
-    }.${config.genode.core.storeBackend} or [ ];
+    storeBackendInputs =
+      lib.optional (config.genode.core.storeBackend == "memory")
+      config.system.build.tarball;
 
     coreInputs =
       # TODO: get rid of this?