diff --git a/sbin/firewall-blacklist-zone.sh b/sbin/firewall-blacklist-zone.sh
index 02cf923..106865c 100755
--- a/sbin/firewall-blacklist-zone.sh
+++ b/sbin/firewall-blacklist-zone.sh
@@ -2,7 +2,7 @@
 
 # Zone (2 letter country code) should be first arg
 if [ -n "$1" ]; then
-  zone=$1
+  zone=${1,,}
 else
   echo "zone not set"
   exit 1