diff --git a/browsers.json b/browsers.json
index c5f1a041de..a4efdcac6d 100644
--- a/browsers.json
+++ b/browsers.json
@@ -8,7 +8,7 @@
     },
     {
       "name": "firefox",
-      "revision": "1258",
+      "revision": "1259",
       "installByDefault": true
     },
     {
diff --git a/src/server/firefox/ffPage.ts b/src/server/firefox/ffPage.ts
index 751dd58b04..876e44ec32 100644
--- a/src/server/firefox/ffPage.ts
+++ b/src/server/firefox/ffPage.ts
@@ -151,7 +151,7 @@ export class FFPage implements PageDelegate {
 
   _onExecutionContextCreated(payload: Protocol.Runtime.executionContextCreatedPayload) {
     const {executionContextId, auxData} = payload;
-    const frame = this._page._frameManager.frame(auxData ? auxData.frameId : null);
+    const frame = this._page._frameManager.frame(auxData.frameId!);
     if (!frame)
       return;
     const delegate = new FFExecutionContext(this._session, executionContextId);
diff --git a/src/server/firefox/protocol.ts b/src/server/firefox/protocol.ts
index d8d5a2b9dd..d0979f2084 100644
--- a/src/server/firefox/protocol.ts
+++ b/src/server/firefox/protocol.ts
@@ -205,6 +205,7 @@ export module Protocol {
     export type addScriptToEvaluateOnNewDocumentReturnValue = void;
     export type addBindingParameters = {
       browserContextId?: string;
+      worldName?: string;
       name: string;
       script: string;
     };
@@ -456,6 +457,7 @@ export module Protocol {
     };
     export type setFileInputFilesReturnValue = void;
     export type addBindingParameters = {
+      worldName?: string;
       name: string;
       script: string;
     };
@@ -699,7 +701,10 @@ export module Protocol {
     };
     export type executionContextCreatedPayload = {
       executionContextId: string;
-      auxData: any;
+      auxData: {
+        frameId?: string;
+        name?: string;
+      };
     }
     export type executionContextDestroyedPayload = {
       executionContextId: string;