diff --git a/app/services/adapters/web-extension.js b/app/services/adapters/web-extension.js
index cc1d91cda8..e2233235b4 100644
--- a/app/services/adapters/web-extension.js
+++ b/app/services/adapters/web-extension.js
@@ -131,6 +131,19 @@ export default class WebExtension extends BasicAdapter {
 function loadEmberDebug() {
   let minimumVersion = config.emberVersionsSupported[0].replace(/\./g, '-');
   let xhr;
+
+  function loadEmberDebugInWebpage() {
+    const waitForEmberLoad = new Promise((resolve) => {
+      if (window.Ember) return resolve();
+      if (window.requireModule && window.requireModule.has('ember')) {
+        return resolve();
+      }
+      window.addEventListener('Ember', resolve, { once: true });
+    });
+    waitForEmberLoad.then(() => {
+      'replace-with-ember-debug';
+    });
+  }
   return new Promise((resolve) => {
     if (!emberDebug) {
       xhr = new XMLHttpRequest();
@@ -142,6 +155,14 @@ function loadEmberDebug() {
         if (xhr.readyState === 4) {
           if (xhr.status === 200) {
             emberDebug = xhr.responseText;
+            // prepare for usage in replace, dollar signs are part of special replacement patterns...
+            emberDebug = emberDebug.replace(/\$/g, '$$$$');
+            emberDebug =
+              '(' +
+              loadEmberDebugInWebpage
+                .toString()
+                .replace("'replace-with-ember-debug';", emberDebug) +
+              ')()';
             resolve(emberDebug);
           }
         }
diff --git a/ember_debug/vendor/startup-wrapper.js b/ember_debug/vendor/startup-wrapper.js
index 18e441a790..ce66618194 100644
--- a/ember_debug/vendor/startup-wrapper.js
+++ b/ember_debug/vendor/startup-wrapper.js
@@ -86,7 +86,7 @@ var EMBER_VERSIONS_SUPPORTED = {{EMBER_VERSIONS_SUPPORTED}};
           });
 
           if (!window.EmberInspector._application) {
-            bootEmberInspector(instance);
+            setTimeout(() => bootEmberInspector(instance), 0);
           }
         }
       });
@@ -131,7 +131,9 @@ var EMBER_VERSIONS_SUPPORTED = {{EMBER_VERSIONS_SUPPORTED}};
     };
 
     // Newest Ember versions >= 1.10
-    window.addEventListener('Ember', triggerOnce, { once: true });
+   
+    const later = () => setTimeout(triggerOnce, 0);
+    window.addEventListener('Ember', later, { once: true });
     // Oldest Ember versions or if this was injected after Ember has loaded.
     onReady(triggerOnce);
   }
@@ -165,20 +167,41 @@ var EMBER_VERSIONS_SUPPORTED = {{EMBER_VERSIONS_SUPPORTED}};
 
     sendApps(adapterInstance, apps);
 
+    function loadInstance(app) {
+      let instance = app.__deprecatedInstance__ || (app._applicationInstances && app._applicationInstances[0]);
+      if (instance) {
+        // App started
+        setupInstanceInitializer(app, callback);
+        callback(instance);
+        return true
+      }
+    }
+
     var app;
     for (var i = 0, l = apps.length; i < l; i++) {
       app = apps[i];
       // We check for the existance of an application instance because
       // in Ember > 3 tests don't destroy the app when they're done but the app has no booted instances.
       if (app._readinessDeferrals === 0) {
-        let instance = app.__deprecatedInstance__ || (app._applicationInstances && app._applicationInstances[0]);
-        if (instance) {
-          // App started
-          setupInstanceInitializer(app, callback);
-          callback(instance);
+        if (loadInstance(app)) {
           break;
         }
       }
+
+      // app already run initializers, but no instance, use _bootPromise and didBecomeReady
+      if(app._bootPromise) {
+        app._bootPromise.then((app) => {
+          loadInstance(app);
+        });
+      }
+
+      app.reopen({
+        didBecomeReady() {
+          this._super.apply(this, arguments);
+          setTimeout(() => loadInstance(app), 0)
+        }
+      });
+
     }
     Ember.Application.initializer({
       name: 'ember-inspector-booted',