diff --git a/src/js/contentscript.js b/src/js/contentscript.js
index 59045fd0f..a9b8522eb 100644
--- a/src/js/contentscript.js
+++ b/src/js/contentscript.js
@@ -1331,7 +1331,8 @@ vAPI.DOMFilterer = class {
 
         // Library of resources is located at:
         // https://github.com/gorhill/uBlock/blob/master/assets/ublock/resources.txt
-        if ( scriptlets ) {
+        if ( scriptlets && typeof self.uBO_scriptletsInjected !== 'boolean' ) {
+            self.uBO_scriptletsInjected = true;
             vAPI.injectScriptlet(document, scriptlets);
             vAPI.injectedScripts = scriptlets;
         }
@@ -1362,9 +1363,7 @@ vAPI.DOMFilterer = class {
         vAPI.messaging.send('contentscript', {
             what: 'retrieveContentScriptParameters',
             url: vAPI.effectiveSelf.location.href,
-            scriptletsInjected:
-                typeof self.uBO_scriptletsInjected === 'boolean' &&
-                self.uBO_scriptletsInjected,
+            needScriptlets: typeof self.uBO_scriptletsInjected !== 'boolean',
         }).then(response => {
             bootstrapPhase1(response);
         });
diff --git a/src/js/messaging.js b/src/js/messaging.js
index c920db9e4..820ac6a42 100644
--- a/src/js/messaging.js
+++ b/src/js/messaging.js
@@ -773,8 +773,8 @@ const retrieveContentScriptParameters = async function(sender, request) {
     // https://github.com/uBlockOrigin/uBlock-issues/issues/688#issuecomment-748179731
     //   For non-network URIs, scriptlet injection is deferred to here. The
     //   effective URL is available here in `request.url`.
-    if ( request.scriptletsInjected !== true ) {
-        scriptletFilteringEngine.injectNow(request);
+    if ( request.needScriptlets ) {
+        response.scriptlets = scriptletFilteringEngine.injectNow(request);
     }
 
     // https://github.com/NanoMeow/QuickReports/issues/6#issuecomment-414516623
diff --git a/src/js/scriptlet-filtering.js b/src/js/scriptlet-filtering.js
index 8c2be9ba9..72dcc444a 100644
--- a/src/js/scriptlet-filtering.js
+++ b/src/js/scriptlet-filtering.js
@@ -432,13 +432,17 @@ scriptletFilteringEngine.injectNow = function(details) {
         matchAboutBlank: true,
         runAt: 'document_start',
     });
-    if ( logEntries === undefined ) { return; }
-    promise.then(results => {
-        if ( Array.isArray(results) === false || results[0] !== 0 ) { return; }
-        for ( const entry of logEntries ) {
-            logOne(entry.tabId, entry.url, entry.token);
-        }
-    });
+    if ( logEntries !== undefined ) {
+        promise.then(results => {
+            if ( Array.isArray(results) === false || results[0] !== 0 ) {
+                return;
+            }
+            for ( const entry of logEntries ) {
+                logOne(entry.tabId, entry.url, entry.token);
+            }
+        });
+    }
+    return scriptlets;
 };
 
 scriptletFilteringEngine.toSelfie = function() {