diff --git a/app/src/common/shared/org/mozilla/vrbrowser/browser/SessionStore.java b/app/src/common/shared/org/mozilla/vrbrowser/browser/SessionStore.java
index c0f7dd4d4..a44fc180c 100644
--- a/app/src/common/shared/org/mozilla/vrbrowser/browser/SessionStore.java
+++ b/app/src/common/shared/org/mozilla/vrbrowser/browser/SessionStore.java
@@ -59,7 +59,7 @@
 import static org.mozilla.vrbrowser.utils.ServoUtils.isServoAvailable;
 
 public class SessionStore implements ContentBlocking.Delegate, GeckoSession.NavigationDelegate,
-        GeckoSession.ProgressDelegate, GeckoSession.ContentDelegate, GeckoSession.TextInputDelegate, 
+        GeckoSession.ProgressDelegate, GeckoSession.ContentDelegate, GeckoSession.TextInputDelegate,
         GeckoSession.PromptDelegate, GeckoSession.MediaDelegate, SharedPreferences.OnSharedPreferenceChangeListener {
 
     private static SessionStore mInstance;
@@ -1042,7 +1042,9 @@ public void onCanGoForward(@NonNull GeckoSession aSession, boolean aCanGoForward
     private String checkYoutubeOverride(String aUri) {
         try {
             Uri uri = Uri.parse(aUri);
-            if (!uri.getHost().toLowerCase().contains("www.youtube.")) {
+            String hostLower = uri.getHost().toLowerCase();
+            if (!hostLower.endsWith(".youtube.com") &&
+                !hostLower.endsWith(".youtube-nocookie.com")) {
                 return null;
             }
             String query = uri.getQueryParameter("disable_polymer");
diff --git a/app/src/main/assets/web_extensions/youtube_webcompat/main.css b/app/src/main/assets/web_extensions/youtube_webcompat/main.css
index f948d9203..2e13a7b52 100644
--- a/app/src/main/assets/web_extensions/youtube_webcompat/main.css
+++ b/app/src/main/assets/web_extensions/youtube_webcompat/main.css
@@ -1,5 +1,6 @@
-/* To hide harmless warning about 360° video playback. */
-div.alert-with-button-renderer,
-ytm-alert-with-button-renderer {
+/* To hide harmless warnings. */
+.alert-with-button-renderer, .ytm-alert-with-button-renderer, ytm-alert-with-button-renderer,
+.ytp-ad-module, ytp-ad-module
+.ytp-generic-popup, ytp-generic-popup {
   display: none;
 }
diff --git a/app/src/main/assets/web_extensions/youtube_webcompat/main.js b/app/src/main/assets/web_extensions/youtube_webcompat/main.js
index 7b39baf02..3a27f5bdd 100644
--- a/app/src/main/assets/web_extensions/youtube_webcompat/main.js
+++ b/app/src/main/assets/web_extensions/youtube_webcompat/main.js
@@ -1,19 +1,174 @@
 (function () {
   // If missing, inject a `<meta name="viewport">` tag to trigger YouTube's mobile layout.
-  const viewport = document.head.querySelector('meta[name="viewport"]');
-  if (!viewport) {
-    viewport = document.createElement('meta');
-    viewport.name = 'viewport';
-    viewport.content = 'width=user-width, initial-scale=1';
-    document.head.appendChild(viewport);
+  window.addEventListener('load', () => {
+    let viewport = document.head.querySelector('meta[name="viewport"]');
+    if (!viewport) {
+      viewport = document.createElement('meta');
+      viewport.name = 'viewport';
+      viewport.content = 'width=device-width, initial-scale=1';
+      document.head.appendChild(viewport);
+    }
+  });
+
+  const LOGTAG = '[firefoxreality:webcompat]'
+  const qs = new URLSearchParams(window.location.search);
+  let retryTimeout = null;
+
+  function getTruthyQS (key) {
+    if (!qs || !qs.has(key)) {
+      return false;
+    }
+    const valueLower = (qs.get('key') || '').trim().toLowerCase();
+    return valueLower === '' || valueLower === '1' || valueLower === 'true' || valueLower === 'yes' || valueLower === 'on';
   }
 
-  // Open the `Settings` menu.
-  document.querySelector('ytp-settings-button, .ytp-settings-button').click();
+  const prefs = {
+    hd: false,
+    quality: 1440,
+    log: qs.get('mozDebug') ? getTruthyQS('mozDebug') : true,
+    retryAttempts: parseInt(qs.get('retryAttempts') || qs.get('retryattempts') || '5', 10),
+    retryTimeout: parseInt(qs.get('retryTimeout') || qs.get('retrytimeout') || '500', 10)
+  };
+
+  const printLog = String(prefs.log) === 'true';
+
+  const log = (...args) => printLog && console.log(LOGTAG, ...args);
+  const logError = (...args) => printLog && console.error(LOGTAG, ...args);
+  const logWarn = (...args) => printLog && console.warn(LOGTAG, ...args);
+
+  const ytImprover = window.ytImprover = (state, attempts) => {
+    if (ytImprover.completed) {
+      return;
+    }
+
+    if (typeof attempts === 'undefined') {
+      attempts = 1;
+    }
+    if (attempts >= prefs.retryAttempts) {
+      return;
+    }
+
+    const player = document.getElementById('movie_player');
+    if (state !== 1 || !player) {
+      attempts++;
+      retryTimeout = setTimeout(() => {
+        ytImprover(state, attempts);
+      }, prefs.retryInterval);
+      return;
+    }
+
+    const levels = player.getAvailableQualityLevels();
+    if (!levels || !levels.length) {
+      logWarn('Cannot read `player.getAvailableQualityLevels()`');
+      return;
+    }
+
+    clearTimeout(retryTimeout);
+    ytImprover.completed = true;
+
+    const prefs.qualities = [
+      'highres', 'h2880', 'hd2160', 'hd1440', 'hd1080', 'hd720', 'large', 'medium', 'small', 'tiny', 'auto'
+    ];
+    const prefs.qualityLabels = {
+      '4320': 'highres', // 8K / 4320p / QUHD
+      '2880': 'hd2880', // 5K / 2880p / UHD+
+      '2160': 'hd2160', // 4K / 2160p / UHD
+      '1440': 'hd1440', // 1440p / QHD
+      '1080': 'hd1080', // 1080p / FHD
+      '720': 'hd720', // 720p / HD
+      '480': 'large', // 480p
+      '360': 'medium', // 360p
+      '240': 'small', // 240p
+      '144': 'tiny', // 144p
+      '0': 'auto'
+    };
 
-  // Select the `Quality` sub-menu.
-  document.querySelector('ytp-settings-menu ytp-menuitem:last-child, .ytp-settings-menu .ytp-menuitem:last-child').click();
+    const getDesiredQuality = () => {
+      const qsQuality = (qs.get('vq') || qs.get('quality') || '').trim().toLowerCase();
+      if (qsQuality) {
+        if (qsQuality in prefs.qualityLabels) {
+          prefs.quality = prefs.qualityLabels[qsQuality];
+        } else {
+          const qsQualityNumber = parseInt(qsQuality, 10);
+          if (Number.isInteger(qsQualityNumber)) {
+            prefs.quality = qsQualityNumber;
+          } else {
+            prefs.quality = qsQuality;
+          }
+        }
+      }
+      prefs.quality = String(prefs.quality).toLowerCase();
+      if (qsQuality === 'auto' || qsQuality === 'default') {
+        prefs.quality = 'auto';
+      }
+      if (prefs.quality in prefs.qualityLabels) {
+        prefs.quality = prefs.qualityLabels[prefs.quality];
+      }
+      return prefs.quality;
+    };
 
-  // Select the best `Quality`.
-  document.querySelector('ytp-quality-menu ytp-menuitem:first-child, .ytp-quality-menu .ytp-menuitem:first-child').click();
+    prefs.quality = getDesiredQuality();
+    if (prefs.quality === 'auto') {
+      return log(`Desired quality is fine (${prefs.quality})`);
+    }
+
+    const currentQuality = player.getPlaybackQuality();
+    if (prefs.quality === currentQuality) {
+      return log(`Current quality is desired quality (${currentQuality})`);
+    }
+
+    const findBestQuality = increase => {
+      if (prefs.quality === 'highest' || prefs.quality === 'best' || prefs.quality === 'max' || prefs.quality === 'maximum') {
+        return levels[0];
+      }
+      if (prefs.quality === 'lowest' || prefs.quality === 'worst' || prefs.quality === 'min' || prefs.quality === 'minimum') {
+        return levels[levels.length - 1];
+      }
+      if (increase) {
+        prefs.quality = prefs.qualities[prefs.qualities.indexOf(prefs.quality) - 1] || levels[0];
+      }
+      const index = levels.indexOf(prefs.quality);
+      if (index !== -1) {
+        return prefs.quality;
+      }
+      return findBestQuality(true);
+    };
+    const newBestQuality = findBestQuality();
+    if (currentQuality === newBestQuality) {
+      return log(`Current quality "${currentQuality}" is the best available quality`);
+    }
+
+    if (!player.setPlaybackQuality) {
+      return logError('`player.setPlaybackQuality` not available');
+    }
+    player.setPlaybackQuality(newBestQuality);
+
+    if (!player.setPlaybackQualityRange) {
+      return logError('`player.setPlaybackQualityRange` not available');
+    }
+    try {
+      player.setPlaybackQualityRange(newBestQuality, newBestQuality);
+    } catch (e) {
+    }
+
+    log(`Changed quality from "${currentQuality}" to "${newBestQuality}"`);
+  };
+
+  if (window.location.pathname.startsWith('/watch')) {
+    const onYouTubePlayerReady = window.onYouTubePlayerReady = evt => {
+      log('`onYouTubePlayerReady` called');
+      window.ytImprover(1);
+      evt.addEventListener('onStateChange', 'ytImprover');
+    };
+
+    window.addEventListener('spfready', () => {
+      log('`spfready` event fired');
+      if (typeof window.ytplayer === 'object' && window.ytplayer.config) {
+        log('`window.ytplayer.config.args.jsapicallback` set');
+        window.ytplayer.config.args.jsapicallback = 'onYouTubePlayerReady';
+      }
+    });
+
+    ytImprover(1);
+  }
 })();
diff --git a/app/src/main/assets/web_extensions/youtube_webcompat/manifest.json b/app/src/main/assets/web_extensions/youtube_webcompat/manifest.json
index 04d38f012..0949b2854 100644
--- a/app/src/main/assets/web_extensions/youtube_webcompat/manifest.json
+++ b/app/src/main/assets/web_extensions/youtube_webcompat/manifest.json
@@ -6,7 +6,8 @@
   "content_scripts": [
     {
       "matches": [
-        "*://*.youtube.com/*"
+        "*://*.youtube.com/*",
+        "*://*.youtube-nocookie.com/*"
       ],
       "css": [
         "main.css"
@@ -14,7 +15,8 @@
       "js": [
         "main.js"
       ],
-      "run_at": "document_end"
+      "run_at": "document_start",
+      "all_frames": true
     }
   ]
 }