diff --git a/openwrt/openwrt-add-jool-ipv4island.sh b/openwrt/openwrt-add-jool-ipv4island.sh
index cac2a24..3b1c7d6 100755
--- a/openwrt/openwrt-add-jool-ipv4island.sh
+++ b/openwrt/openwrt-add-jool-ipv4island.sh
@@ -1,6 +1,6 @@
 #!/bin/sh
 
-if [ $# -ne 3 ]; then
+if [ $# -ne 2 ]; then
     echo "$0 ip-address nat64-prefix"
     echo "    ip-address: where to find the OpenWRT device"
     echo "    nat64-prefix: which network to use for INCOMING NAT64 (often 2a0a:e5c1:XXX:b00::/96"