diff --git a/avocado/utils/pmem.py b/avocado/utils/pmem.py
index bdf6219a88..5dc82ec648 100644
--- a/avocado/utils/pmem.py
+++ b/avocado/utils/pmem.py
@@ -463,7 +463,7 @@ def write_infoblock(self, namespace="", stdout=False, output=None, **kwargs):
             "size": "-s %s",
             "align": "-a %s",
             "uuid": "-u %s",
-            "parent_uuid": "-p %",
+            "parent_uuid": "-p %s",
             "offset": "-O %s",
         }
         args = ""