diff --git a/roles/raspbian/tasks/main.yml b/roles/raspbian/tasks/main.yml
index 69800e9..86b222a 100644
--- a/roles/raspbian/tasks/main.yml
+++ b/roles/raspbian/tasks/main.yml
@@ -21,7 +21,7 @@
     cmd: 'iptables -F'
   register: flush_iptables
   changed_when:
-    - flush_iptables.rc == 0 and flush_iptables.stdout != ""
+    - flush_iptables.rc == 0 and flush_iptables.stdout_lines.count == 0
   when:
     - ansible_facts.distribution_release is search("buster")