diff --git a/python/lvmecp/actor/commands/dome.py b/python/lvmecp/actor/commands/dome.py
index e24385d..3d92ccc 100644
--- a/python/lvmecp/actor/commands/dome.py
+++ b/python/lvmecp/actor/commands/dome.py
@@ -67,6 +67,8 @@ async def status(command: ECPCommand):
     """Returns the status of the dome."""
 
     status = await command.actor.plc.dome.update()
+    if status is None:
+        return command.fail("Failed retrieving dome status.")
 
     if status & DomeStatus.MOVING:
         command.warning("Dome is moving!!!")
diff --git a/python/lvmecp/dome.py b/python/lvmecp/dome.py
index e865ac3..3880b90 100644
--- a/python/lvmecp/dome.py
+++ b/python/lvmecp/dome.py
@@ -36,6 +36,7 @@ async def _update_internal(self):
 
         dome_status = SimpleNamespace(**dome_registers)
 
+        assert self.flag
         new_status = self.flag(0)
 
         if dome_status.drive_state:
@@ -85,6 +86,8 @@ async def _move(self, open: bool, force: bool = False):
 
         await self.update()
 
+        assert self.status is not None and self.flag is not None
+
         if self.status & self.flag.UNKNOWN:
             raise DomeError("Dome is in unknown state.")
 
@@ -145,6 +148,9 @@ async def stop(self):
         drive_enabled = await self.plc.modbus["drive_enabled"].get()
         status = await self.update()
 
+        if status is None or self.flag is None:
+            raise RuntimeError("Failed retrieving dome status.")
+
         if not drive_enabled:
             return
 
diff --git a/python/lvmecp/module.py b/python/lvmecp/module.py
index 25a6121..ae40b8b 100644
--- a/python/lvmecp/module.py
+++ b/python/lvmecp/module.py
@@ -91,7 +91,6 @@ async def update(self, force_output: bool = False, **notifier_kwargs):
         try:
             new_status = await self._update_internal()
         except Exception as err:
-            raise
             log.warning(f"{self.name}: failed updating status: {err}")
             new_status = self.flag(self.flag.__unknown__) if self.flag else None
 
diff --git a/python/lvmecp/safety.py b/python/lvmecp/safety.py
index 8da3e9e..8491209 100644
--- a/python/lvmecp/safety.py
+++ b/python/lvmecp/safety.py
@@ -72,4 +72,6 @@ async def is_remote(self):
             return True
 
         await self.update()
+        assert self.status is not None and self.flag is not None
+
         return not (self.status & self.flag.LOCAL)