diff --git a/platform/firefox/bootstrap.js b/platform/firefox/bootstrap.js
index 0605b8378..252ea622e 100644
--- a/platform/firefox/bootstrap.js
+++ b/platform/firefox/bootstrap.js
@@ -28,31 +28,13 @@
 
 let bgProcess;
 const hostName = 'ublock';
-const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
-const restartObserver = {
-    get observer() {
-        return Cc["@mozilla.org/observer-service;1"]
-            .getService(Ci.nsIObserverService);
+const restartListener = {
+    get messageManager() {
+        return Components.classes['@mozilla.org/parentprocessmessagemanager;1']
+            .getService(Components.interfaces.nsIMessageListenerManager);
     },
 
-    QueryInterface: (function() {
-        let {XPCOMUtils} = Cu['import']('resource://gre/modules/XPCOMUtils.jsm', {});
-
-        return XPCOMUtils.generateQI([
-            Ci.nsIObserver,
-            Ci.nsISupportsWeakReference
-        ]);
-    })(),
-
-    register: function() {
-        this.observer.addObserver(this, hostName + '-restart', true);
-    },
-
-    unregister: function() {
-        this.observer.removeObserver(this, hostName + '-restart');
-    },
-
-    observe: function() {
+    receiveMessage: function() {
         shutdown();
         startup();
     }
@@ -66,8 +48,8 @@ function startup(data, reason) {
             this.removeEventListener(e.type, onReady);
         }
 
-        let hDoc = Cc['@mozilla.org/appshell/appShellService;1']
-            .getService(Ci.nsIAppShellService)
+        let hDoc = Components.classes['@mozilla.org/appshell/appShellService;1']
+            .getService(Components.interfaces.nsIAppShellService)
             .hiddenDOMWindow.document;
 
         bgProcess = hDoc.documentElement.appendChild(
@@ -77,7 +59,11 @@ function startup(data, reason) {
             'src',
             'chrome://' + hostName + '/content/background.html'
         );
-        restartObserver.register();
+
+        restartListener.messageManager.addMessageListener(
+            hostName + '-restart',
+            restartListener
+        );
     };
 
     if ( reason !== APP_STARTUP ) {
@@ -85,8 +71,8 @@ function startup(data, reason) {
         return;
     }
 
-    let ww = Cc['@mozilla.org/embedcomp/window-watcher;1']
-                .getService(Ci.nsIWindowWatcher);
+    let ww = Components.classes['@mozilla.org/embedcomp/window-watcher;1']
+                .getService(Components.interfaces.nsIWindowWatcher);
 
     ww.registerNotification({
         observe: function(win) {
@@ -107,7 +93,10 @@ function shutdown(data, reason) {
 
     // Remove the restartObserver only when the extension is being disabled
     if ( data !== undefined ) {
-        restartObserver.unregister();
+        restartListener.messageManager.removeMessageListener(
+            hostName + '-restart',
+            restartListener
+        );
     }
 }
 
@@ -115,8 +104,8 @@ function shutdown(data, reason) {
 
 function install() {
     // https://bugzil.la/719376
-    Cc['@mozilla.org/intl/stringbundle;1']
-        .getService(Ci.nsIStringBundleService).flushBundles();
+    Components.classes['@mozilla.org/intl/stringbundle;1']
+        .getService(Components.interfaces.nsIStringBundleService).flushBundles();
 }
 
 /******************************************************************************/
diff --git a/platform/firefox/frameModule.js b/platform/firefox/frameModule.js
index 2b1a912df..8d859c021 100644
--- a/platform/firefox/frameModule.js
+++ b/platform/firefox/frameModule.js
@@ -19,20 +19,17 @@
     Home: https://github.com/gorhill/uBlock
 */
 
-/* global Services, Components, XPCOMUtils, __URI__ */
-
 'use strict';
 
 /******************************************************************************/
 
 this.EXPORTED_SYMBOLS = ['contentObserver'];
 
-const {interfaces: Ci, utils: Cu} = Components;
-const appName = __URI__.match(/:\/\/([^\/]+)/)[1];
+const {interfaces: Ci, utils: Cu} = this.Components;
+const appName = this.__URI__.match(/:\/\/([^\/]+)/)[1];
 
-Cu['import']('resource://gre/modules/Services.jsm');
-Cu['import']('resource://gre/modules/XPCOMUtils.jsm');
-// Cu['import']('resource://gre/modules/devtools/Console.jsm');
+Cu.import('resource://gre/modules/Services.jsm');
+Cu.import('resource://gre/modules/devtools/Console.jsm');
 
 /******************************************************************************/
 
@@ -66,12 +63,16 @@ const contentObserver = {
                 .getService(Ci.nsICategoryManager);
     },
 
-    QueryInterface: XPCOMUtils.generateQI([
-        Ci.nsIFactory,
-        Ci.nsIObserver,
-        Ci.nsIContentPolicy,
-        Ci.nsISupportsWeakReference
-    ]),
+    QueryInterface: (function() {
+        let {XPCOMUtils} = Cu['import']('resource://gre/modules/XPCOMUtils.jsm', {});
+
+        return XPCOMUtils.generateQI([
+            Ci.nsIFactory,
+            Ci.nsIObserver,
+            Ci.nsIContentPolicy,
+            Ci.nsISupportsWeakReference
+        ]);
+    })(),
 
     createInstance: function(outer, iid) {
         if ( outer ) {
@@ -117,7 +118,7 @@ const contentObserver = {
             return this.ACCEPT;
         }
 
-        let opener;
+        var opener;
 
         if ( location.scheme !== 'http' && location.scheme !== 'https' ) {
             if ( type !== this.MAIN_FRAME ) {
@@ -208,6 +209,7 @@ const contentObserver = {
                 this.initContentScripts(win);
             }
 
+            // What about data: and about:blank?
             return;
         }
 
diff --git a/platform/firefox/vapi-background.js b/platform/firefox/vapi-background.js
index c076b3d55..6f26f1872 100644
--- a/platform/firefox/vapi-background.js
+++ b/platform/firefox/vapi-background.js
@@ -19,8 +19,6 @@
     Home: https://github.com/gorhill/uBlock
 */
 
-/* global Services, XPCOMUtils, CustomizableUI */
-
 // For background page
 
 /******************************************************************************/
@@ -33,9 +31,7 @@
 
 const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
 
-Cu['import']('resource://gre/modules/Services.jsm');
-Cu['import']('resource://gre/modules/XPCOMUtils.jsm');
-Cu['import']('resource:///modules/CustomizableUI.jsm');
+Cu.import('resource://gre/modules/Services.jsm');
 
 /******************************************************************************/
 
@@ -53,8 +49,10 @@ vAPI.app = {
 /******************************************************************************/
 
 vAPI.app.restart = function() {
-    // Observing in bootstrap.js
-    Services.obs.notifyObservers(null, location.host + '-restart', null);
+    // Listening in bootstrap.js
+    Cc['@mozilla.org/childprocessmessagemanager;1']
+        .getService(Ci.nsIMessageSender)
+        .sendAsyncMessage(location.host + '-restart');
 };
 
 /******************************************************************************/
@@ -641,6 +639,8 @@ vAPI.toolbarButton = {
 /******************************************************************************/
 
 vAPI.toolbarButton.init = function() {
+    const {CustomizableUI} = Cu.import('resource:///modules/CustomizableUI.jsm', {});
+
     CustomizableUI.createWidget({
         id: this.widgetId,
         type: 'view',
@@ -936,12 +936,16 @@ var httpObserver = {
                 .getService(Ci.nsICategoryManager);
     },
 
-    QueryInterface: XPCOMUtils.generateQI([
-        Ci.nsIFactory,
-        Ci.nsIObserver,
-        Ci.nsIChannelEventSink,
-        Ci.nsISupportsWeakReference
-    ]),
+    QueryInterface: (function() {
+        var {XPCOMUtils} = Cu.import('resource://gre/modules/XPCOMUtils.jsm', {});
+
+        return XPCOMUtils.generateQI([
+            Ci.nsIFactory,
+            Ci.nsIObserver,
+            Ci.nsIChannelEventSink,
+            Ci.nsISupportsWeakReference
+        ]);
+    })(),
 
     createInstance: function(outer, iid) {
         if ( outer ) {
@@ -1048,12 +1052,12 @@ var httpObserver = {
             }
 
             try {
+                // [tabId, type, sourceTabId - given if it was a popup]
                 channelData = channel.getProperty(location.host + 'reqdata');
             } catch (ex) {
                 return;
             }
 
-            // [tabId, type, sourceTabId - given if it was a popup]
             if ( !channelData || channelData[0] !== this.MAIN_FRAME ) {
                 return;
             }
@@ -1402,7 +1406,7 @@ window.addEventListener('unload', function() {
 
     // frameModule needs to be cleared too
     var frameModule = {};
-    Cu['import'](vAPI.getURL('frameModule.js'), frameModule);
+    Cu.import(vAPI.getURL('frameModule.js'), frameModule);
     frameModule.contentObserver.unregister();
     Cu.unload(vAPI.getURL('frameModule.js'));
 });