diff --git a/flatpak/page.kramo.Cartridges.Devel.json b/flatpak/page.kramo.Cartridges.Devel.json
index 1c895a0..5dfe228 100644
--- a/flatpak/page.kramo.Cartridges.Devel.json
+++ b/flatpak/page.kramo.Cartridges.Devel.json
@@ -9,7 +9,9 @@
     "--socket=fallback-x11",
     "--device=dri",
     "--socket=wayland",
-    "--talk-name=org.freedesktop.Flatpak"
+    "--talk-name=org.freedesktop.Flatpak",
+    "--filesystem=host:ro",
+    "--filesystem=~/.var/app/com.valvesoftware.Steam/data/Steam/:ro"
   ],
   "cleanup": [
     "/include",
@@ -27,9 +29,7 @@
       "name": "cartridges",
       "builddir": true,
       "buildsystem": "meson",
-      "config-opts": [
-        "-Dprofile=development"
-      ],
+      "config-opts": ["-Dprofile=development"],
       "sources": [
         {
           "type": "dir",