diff --git a/.github/workflows/shipdriver.yml b/.github/workflows/shipdriver.yml
index 51fe1486..362708c8 100644
--- a/.github/workflows/shipdriver.yml
+++ b/.github/workflows/shipdriver.yml
@@ -17,6 +17,7 @@ jobs:
       CLOUDSMITH_STABLE_REPO: ${{ secrets.CLOUDSMITH_STABLE_REPO}}
       CLOUDSMITH_UNSTABLE_REPO: ${{ secrets.CLOUDSMITH_UNSTABLE_REPO}}
       CLOUDSMITH_BETA_REPO: ${{ secrets.CLOUDSMITH_BETA_REPO}}
+      FLATPAK_BRANCH: beta
 
     steps:
       - name: Git checkout
diff --git a/ci/github-build-flatpak.sh b/ci/github-build-flatpak.sh
index df20a2fe..a1a5ab2d 100755
--- a/ci/github-build-flatpak.sh
+++ b/ci/github-build-flatpak.sh
@@ -14,26 +14,25 @@ sudo dnf install -y -q cmake flatpak-builder flatpak gcc-c++ tar
 
 # For now, horrible hack: aarch 64 builds are using the updated runtime
 # 20.08 and the opencpn beta version using same runtime.
-case $(uname -m) in
-    arm64|aarch64)
+if [ "$FLATPAK_BRANCH" = 'beta' ]; then
         flatpak install --user -y flathub org.freedesktop.Sdk//20.08 >/dev/null
         flatpak remote-add --user --if-not-exists flathub-beta \
             https://flathub.org/beta-repo/flathub-beta.flatpakrepo
         flatpak install --user -y --or-update flathub-beta \
             org.opencpn.OpenCPN >/dev/null
         sed -i '/sdk:/s/18.08/20.08/'  flatpak/org.opencpn.*.yaml
-        ;;
-    *)
+else
         flatpak install --user -y flathub org.freedesktop.Sdk//18.08 >/dev/null
         flatpak remote-add --user --if-not-exists flathub \
             https://flathub.org/repo/flathub.flatpakrepo
         flatpak install --user -y --or-update flathub \
             org.opencpn.OpenCPN >/dev/null
-        ;;
-esac
+        FLATPAK_BRANCH='stable'
+fi
 
-# Patch the runtime version so it matches the nightly builds'
-sed -i '/^runtime-version/s/:.*/: stable/' flatpak/$MANIFEST
+# Patch the runtime version so it matches the nightly builds
+# or beta as appropriate.
+sed -i "/^runtime-version/s/:.*/: $FLATPAK_BRANCH/" flatpak/$MANIFEST
 
 # Configure and build the plugin tarball and metadata.
 mkdir build; cd build
diff --git a/flatpak/org.opencpn.OpenCPN.Plugin.shipdriver.yaml b/flatpak/org.opencpn.OpenCPN.Plugin.shipdriver.yaml
index a7c4373a..35034c59 100644
--- a/flatpak/org.opencpn.OpenCPN.Plugin.shipdriver.yaml
+++ b/flatpak/org.opencpn.OpenCPN.Plugin.shipdriver.yaml
@@ -1,3 +1,9 @@
+#
+# Branches and runtimes:
+#   - master     Nigthly builds, 18.08 runtime
+#   - beta       Flathub beta branch, aarch64 with 20.08 runtime.
+#   - stable     Flathub main branch, x86_64 with 18.08 runtime.
+#
 id: org.opencpn.OpenCPN.Plugin.shipdriver
 runtime: org.opencpn.OpenCPN
 runtime-version: stable   # official build at flathub