diff --git a/check-lte-firmware-upgrade.rsc b/check-lte-firmware-upgrade.rsc
index 92ebe51..a2aec01 100644
--- a/check-lte-firmware-upgrade.rsc
+++ b/check-lte-firmware-upgrade.rsc
@@ -12,6 +12,10 @@
 
 :global SentLteFirmwareUpgradeNotification;
 
+:global ScriptLock;
+
+$ScriptLock $0;
+
 :if ([ :typeof $SentLteFirmwareUpgradeNotification ] != "array") do={
   :global SentLteFirmwareUpgradeNotification ({});
 }