diff --git a/katsu/modules/base/desktop.yaml b/katsu/modules/base/desktop.yaml
new file mode 100644
index 0000000..2416dfc
--- /dev/null
+++ b/katsu/modules/base/desktop.yaml
@@ -0,0 +1,11 @@
+scripts:
+  post:
+    - id: polycrystal
+      name: Install Flatpaks via Polycrystal
+      file: polycrystal.sh
+
+dnf:
+  releasever: 41
+  exec: dnf4
+  packages:
+    - "@default-flatpak-support"
diff --git a/katsu/modules/base/polycrystal.sh b/katsu/modules/base/polycrystal.sh
new file mode 100644
index 0000000..1684304
--- /dev/null
+++ b/katsu/modules/base/polycrystal.sh
@@ -0,0 +1,31 @@
+#!/bin/bash -x
+set -euo pipefail
+
+# Hack from https://gist.github.com/jlebon/fb6e7c6dcc3ce17d3e2a86f5938ec033
+
+cleanup() {
+    chmod u-s /mnt/mock-mount/usr/bin/bwrap
+    for mnt in sys proc dev/pts dev; do
+        umount /mnt/mock-mount/$mnt
+    done
+    umount /mnt/mock-mount
+    umount /mnt/mock-mount
+}
+
+if [ -x "$(command -v polycrystal)" ]; then
+    trap cleanup EXIT
+    mkdir -p /mnt/mock-mount
+    mount --bind / /mnt/mock-mount
+    mount --make-private /mnt/mock-mount
+    mount --bind /mnt/mock-mount /mnt/mock-mount
+    for mnt in proc sys dev dev/pts; do
+        mount --bind /$mnt /mnt/mock-mount/$mnt
+    done
+
+    # For some reason, our hack to get bwrap to work in a chroot also breaks user namespaces
+    # I can't figure out why, so we'll just setuid bwrap for now
+    # YOU MUST REMOVE THE SETUID BIT AFTER RUNNING THIS SCRIPT WHICH WE DO IN THE CLEANUP FUNCTION AND HERE
+    chmod u+s /mnt/mock-mount/usr/bin/bwrap
+    chroot /mnt/mock-mount bash -c 'polycrystal'
+    chmod u-s /mnt/mock-mount/usr/bin/bwrap
+fi
diff --git a/katsu/modules/flagship/base-disk-aarch64.yaml b/katsu/modules/flagship/base-disk-aarch64.yaml
index 68e8dcd..ce1d8ce 100644
--- a/katsu/modules/flagship/base-disk-aarch64.yaml
+++ b/katsu/modules/flagship/base-disk-aarch64.yaml
@@ -11,6 +11,7 @@ distro: Ultramarine Linux 41 (Flagship Edition)
 import:
   - ../base/base.yaml
   - ../base/base-disk.yaml
+  - ../base/desktop.yaml
   - flagship.yaml
 
 scripts:
diff --git a/katsu/modules/flagship/base-disk-x86_64.yaml b/katsu/modules/flagship/base-disk-x86_64.yaml
index a8b293d..13875e2 100644
--- a/katsu/modules/flagship/base-disk-x86_64.yaml
+++ b/katsu/modules/flagship/base-disk-x86_64.yaml
@@ -11,6 +11,7 @@ distro: Ultramarine Linux 41 (Flagship Edition)
 import:
   - ../base/base.yaml
   - ../base/base-disk.yaml
+  - ../base/desktop.yaml
   - flagship.yaml
 
 scripts:
diff --git a/katsu/modules/flagship/flagship-live.yaml b/katsu/modules/flagship/flagship-live.yaml
index 9db8578..fc8e0b5 100644
--- a/katsu/modules/flagship/flagship-live.yaml
+++ b/katsu/modules/flagship/flagship-live.yaml
@@ -3,6 +3,7 @@ builder: dnf
 import:
   - ../base/base.yaml
   - ../live/live.yaml
+  - ../base/desktop.yaml
   - flagship.yaml
 
 distro: Ultramarine Linux 41 (Flagship Edition)
diff --git a/katsu/modules/gnome/base-disk-aarch64.yaml b/katsu/modules/gnome/base-disk-aarch64.yaml
index 2d39b64..7ff7d95 100644
--- a/katsu/modules/gnome/base-disk-aarch64.yaml
+++ b/katsu/modules/gnome/base-disk-aarch64.yaml
@@ -11,6 +11,7 @@ distro: Ultramarine Linux 41 (GNOME Edition)
 import:
   - ../base/base.yaml
   - ../base/base-disk.yaml
+  - ../base/desktop.yaml
   - gnome.yaml
 
 scripts:
diff --git a/katsu/modules/gnome/base-disk-x86_64.yaml b/katsu/modules/gnome/base-disk-x86_64.yaml
index 8a01b58..fe4adc5 100644
--- a/katsu/modules/gnome/base-disk-x86_64.yaml
+++ b/katsu/modules/gnome/base-disk-x86_64.yaml
@@ -11,6 +11,7 @@ distro: Ultramarine Linux 41 (GNOME Edition)
 import:
   - ../base/base.yaml
   - ../base/base-disk.yaml
+  - ../base/desktop.yaml
   - gnome.yaml
 
 scripts:
diff --git a/katsu/modules/gnome/gnome-live.yaml b/katsu/modules/gnome/gnome-live.yaml
index f42b5f9..f4be07e 100644
--- a/katsu/modules/gnome/gnome-live.yaml
+++ b/katsu/modules/gnome/gnome-live.yaml
@@ -3,6 +3,7 @@ builder: dnf
 import:
   - ../base/base.yaml
   - ../live/live.yaml
+  - ../base/desktop.yaml
   - gnome.yaml
 
 distro: Ultramarine GNOME 41
diff --git a/katsu/modules/plasma/base-disk-aarch64.yaml b/katsu/modules/plasma/base-disk-aarch64.yaml
index c305ffb..23641f9 100644
--- a/katsu/modules/plasma/base-disk-aarch64.yaml
+++ b/katsu/modules/plasma/base-disk-aarch64.yaml
@@ -11,6 +11,7 @@ distro: Ultramarine Linux 41 (Plasma Edition)
 import:
   - ../base/base.yaml
   - ../base/base-disk.yaml
+  - ../base/desktop.yaml
   - plasma.yaml
   - plasma-disk.yaml
 
diff --git a/katsu/modules/plasma/base-disk-x86_64.yaml b/katsu/modules/plasma/base-disk-x86_64.yaml
index d3fcb41..e714274 100644
--- a/katsu/modules/plasma/base-disk-x86_64.yaml
+++ b/katsu/modules/plasma/base-disk-x86_64.yaml
@@ -11,6 +11,7 @@ distro: Ultramarine Linux 41 (Plasma Edition)
 import:
   - ../base/base.yaml
   - ../base/base-disk.yaml
+  - ../base/desktop.yaml
   - plasma.yaml
   - plasma-disk.yaml
 
diff --git a/katsu/modules/plasma/plasma-live.yaml b/katsu/modules/plasma/plasma-live.yaml
index 28405dc..72a567a 100644
--- a/katsu/modules/plasma/plasma-live.yaml
+++ b/katsu/modules/plasma/plasma-live.yaml
@@ -3,6 +3,7 @@ builder: dnf
 import:
   - ../base/base.yaml
   - ../live/live.yaml
+  - ../base/desktop.yaml
   - plasma.yaml
 
 distro: Ultramarine Linux 41 (Plasma Edition)
diff --git a/katsu/modules/xfce/base-disk-aarch64.yaml b/katsu/modules/xfce/base-disk-aarch64.yaml
index 1bde1d9..538ab25 100644
--- a/katsu/modules/xfce/base-disk-aarch64.yaml
+++ b/katsu/modules/xfce/base-disk-aarch64.yaml
@@ -11,6 +11,7 @@ distro: Ultramarine Linux 41 (Xfce Edition)
 import:
   - ../base/base.yaml
   - ../base/base-disk.yaml
+  - ../base/desktop.yaml
   - xfce.yaml
 
 scripts:
diff --git a/katsu/modules/xfce/base-disk-x86_64.yaml b/katsu/modules/xfce/base-disk-x86_64.yaml
index d7c03fa..3bdc81e 100644
--- a/katsu/modules/xfce/base-disk-x86_64.yaml
+++ b/katsu/modules/xfce/base-disk-x86_64.yaml
@@ -11,6 +11,7 @@ distro: Ultramarine Linux 41 (Xfce Edition)
 import:
   - ../base/base.yaml
   - ../base/base-disk.yaml
+  - ../base/desktop.yaml
   - xfce.yaml
 
 scripts:
diff --git a/katsu/modules/xfce/xfce-live.yaml b/katsu/modules/xfce/xfce-live.yaml
index a1e3bc7..0fde06a 100644
--- a/katsu/modules/xfce/xfce-live.yaml
+++ b/katsu/modules/xfce/xfce-live.yaml
@@ -3,6 +3,7 @@ builder: dnf
 import:
   - ../base/base.yaml
   - ../live/live.yaml
+  - ../base/desktop.yaml
   - xfce.yaml
 
 distro: Ultramarine Linux 41 (Xfce Edition)