diff --git a/platform/mv3/extension/js/background.js b/platform/mv3/extension/js/background.js
index c8183e925..791625d2a 100644
--- a/platform/mv3/extension/js/background.js
+++ b/platform/mv3/extension/js/background.js
@@ -38,6 +38,8 @@ import {
 } from './ruleset-manager.js';
 
 import {
+    MODE_BASIC,
+    MODE_OPTIMAL,
     getDefaultFilteringMode,
     getFilteringMode,
     getTrustedSites,
@@ -136,7 +138,7 @@ async function onPermissionsRemoved() {
     const modified = await syncWithBrowserPermissions();
     if ( modified === false ) { return false; }
     const afterMode = await getDefaultFilteringMode();
-    if ( beforeMode > 1 && afterMode <= 1 ) {
+    if ( beforeMode > MODE_BASIC && afterMode <= MODE_BASIC ) {
         updateDynamicRules();
     }
     registerInjectables();
@@ -420,9 +422,19 @@ async function start() {
     );
 
     if ( firstRun ) {
+        const enableOptimal = await hasOmnipotence();
+        if ( enableOptimal ) {
+            const afterLevel = await setDefaultFilteringMode(MODE_OPTIMAL);
+            if ( afterLevel === MODE_OPTIMAL ) {
+                updateDynamicRules();
+                registerInjectables();
+            }
+        }
         const disableFirstRunPage = await adminRead('disableFirstRunPage');
         if ( disableFirstRunPage !== true ) {
             runtime.openOptionsPage();
+        } else {
+            firstRun = false;
         }
     }
 }
diff --git a/platform/mv3/extension/js/settings.js b/platform/mv3/extension/js/settings.js
index 6f50055df..c916c4657 100644
--- a/platform/mv3/extension/js/settings.js
+++ b/platform/mv3/extension/js/settings.js
@@ -316,7 +316,7 @@ dom.on('#showBlockedCount input[type="checkbox"]', 'change', ev => {
 
 function renderTrustedSites() {
     const textarea = qs$('#trustedSites');
-    const hostnames = cachedRulesetData.trustedSites;
+    const hostnames = cachedRulesetData.trustedSites || [];
     textarea.value = hostnames.map(hn => punycode.toUnicode(hn)).join('\n');
     if ( textarea.value !== '' ) {
         textarea.value += '\n';
@@ -325,7 +325,7 @@ function renderTrustedSites() {
 
 function changeTrustedSites() {
     const hostnames = getStagedTrustedSites();
-    const hash = hashFromIterable(cachedRulesetData.trustedSites);
+    const hash = hashFromIterable(cachedRulesetData.trustedSites || []);
     if ( hashFromIterable(hostnames) === hash ) { return; }
     sendMessage({
         what: 'setTrustedSites',