diff --git a/.gitea/workflows/build-flatpak.yml b/.gitea/workflows/build-flatpak.yml
index be4574c..53a67a3 100644
--- a/.gitea/workflows/build-flatpak.yml
+++ b/.gitea/workflows/build-flatpak.yml
@@ -152,6 +152,7 @@ jobs:
           [Flatpak Repo]
           Title=HeiniRemote Agent
           Url=$BASE
+          RuntimeRepo=https://dl.flathub.org/repo/flathub.flatpakrepo
           Homepage=https://pc-heini.de/
           Comment=HeiniRemote remote maintenance agent as a Flatpak
           Description=Install the HeiniRemote agent on any Linux distribution via Flatpak.
diff --git a/heiniremote.flatpakrepo b/heiniremote.flatpakrepo
index c8a3b80..b0d93ca 100644
--- a/heiniremote.flatpakrepo
+++ b/heiniremote.flatpakrepo
@@ -4,6 +4,9 @@ Title=HeiniRemote Agent
 # so the canonical copy to use is:
 #   https://git.pc-heini.de/pc-heini/HeiniRemote-AgentFlatpak/raw/branch/pages/heiniremote.flatpakrepo
 Url=https://git.pc-heini.de/pc-heini/HeiniRemote-AgentFlatpak/raw/branch/pages
+# Lets `flatpak install` pull the freedesktop runtime on a system that has no
+# Flathub remote yet (e.g. a fresh Ubuntu after `apt install flatpak`).
+RuntimeRepo=https://dl.flathub.org/repo/flathub.flatpakrepo
 Homepage=https://pc-heini.de/
 Comment=HeiniRemote remote maintenance agent as a Flatpak
 Description=Install the HeiniRemote agent on any Linux distribution via Flatpak.