diff --git a/otaclient/app/boot_control/_grub.py b/otaclient/app/boot_control/_grub.py
index a0352aacf..f24cbc505 100644
--- a/otaclient/app/boot_control/_grub.py
+++ b/otaclient/app/boot_control/_grub.py
@@ -357,10 +357,9 @@ def _detect_active_slot(self) -> Tuple[str, str]:
         """
         dev_path = CMDHelperFuncs.get_current_rootfs_dev()
         _dev_path_ma = self.DEV_PATH_PA.match(dev_path)
-        assert _dev_path_ma and (
-            _pid := _dev_path_ma.group("partition_id")
-        ), f"failed to parse active device path: {dev_path=}"
+        assert _dev_path_ma, f"dev path is invalid for OTA: {dev_path}"
 
+        _pid = _dev_path_ma.group("partition_id")
         slot_name = f"{self.SLOT_NAME_PREFIX}{_pid}"
         return slot_name, dev_path