diff --git a/.cockpit-ci/container b/.cockpit-ci/container
index 17f452c096b3..8867af123b97 100644
--- a/.cockpit-ci/container
+++ b/.cockpit-ci/container
@@ -1 +1 @@
-ghcr.io/cockpit-project/tasks:2024-12-28
+ghcr.io/cockpit-project/tasks:2025-01-04
diff --git a/.github/workflows/flatpak-test.yml b/.github/workflows/flatpak-test.yml
index 785706201a7b..f9ea3c9631a6 100644
--- a/.github/workflows/flatpak-test.yml
+++ b/.github/workflows/flatpak-test.yml
@@ -4,7 +4,7 @@ on:
 
 jobs:
   run:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     permissions: {}
     timeout-minutes: 20
     steps:
diff --git a/src/cockpit/channels/filesystem.py b/src/cockpit/channels/filesystem.py
index 24a54cbc7d3e..4c10790de72b 100644
--- a/src/cockpit/channels/filesystem.py
+++ b/src/cockpit/channels/filesystem.py
@@ -562,6 +562,7 @@ def do_open(self, options: JsonObject) -> None:
             try:
                 fd = Handle.open(self.path, os.O_PATH if self.follow else os.O_PATH | os.O_NOFOLLOW)
             except OSError as exc:
+                assert exc.errno  # noqa: PT017 - mypy thinks that errno can be None
                 self.report_error(exc.errno)
             else:
                 self.report_initial_state(fd)