diff --git a/ext/src/shim/index.ts b/ext/src/shim/index.ts
index edf94ca..6bf581d 100755
--- a/ext/src/shim/index.ts
+++ b/ext/src/shim/index.ts
@@ -21,6 +21,8 @@ onMessage(message => {
         case "shim:/initialized": {
             const bridgeInfo = message.data;
 
+            cast.isAvailable = true;
+
             // Call page's API loaded function if defined
             const readyFunction = global.__onGCastApiAvailable;
             if (readyFunction && typeof readyFunction === "function") {