diff --git a/discovery.php b/discovery.php
index 6c376e962..088bff22b 100755
--- a/discovery.php
+++ b/discovery.php
@@ -31,7 +31,7 @@ elseif ($options['h']) {
   }
 }
 
-if ($options['i'] && isset($options['n'])) {
+if (isset($options['i']) && $options['i'] && isset($options['n'])) {
   $where = "AND MOD(device_id,".$options['i'].") = '" . $options['n'] . "'";
   $doing = $options['n'] ."/".$options['i'];
 }