diff --git a/README.upgrade b/README.upgrade
index 5189ced..fb3563e 100644
--- a/README.upgrade
+++ b/README.upgrade
@@ -22,7 +22,7 @@ systemctl stop cryptpad
 # Stop iptables firewall
 #
 ipt-firewall-server flush
-ip6t-firewall-server
+ip6t-firewall-server flush
 
 
 # Login as CryptPad user