--- a/browser/base/content/test/general/browser_subframe_favicons_not_used.js
+++ b/browser/base/content/test/general/browser_subframe_favicons_not_used.js
@@ -4,15 +4,18 @@ function test() {
   waitForExplicitFinish();
 
   let testPath = getRootDirectory(gTestPath);
 
   let tab = BrowserTestUtils.addTab(gBrowser, testPath + "file_bug970276_popup1.html");
 
   tab.linkedBrowser.addEventListener("load", function() {
     let expectedIcon = testPath + "file_bug970276_favicon1.ico";
-    is(gBrowser.getIcon(tab), expectedIcon, "Correct icon.");
+    BrowserTestUtils.waitForCondition(() => true, "wait for loadFavicon to finish", 100)
+    .then(() => {
+      is(gBrowser.getIcon(tab), expectedIcon, "Correct icon.");
 
-    gBrowser.removeTab(tab);
+      gBrowser.removeTab(tab);
 
-    finish();
+      finish();
+    });
   }, {capture: true, once: true});
 }

--- a/browser/components/sessionstore/test/browser_attributes.js
+++ b/browser/components/sessionstore/test/browser_attributes.js
@@ -17,16 +17,18 @@ add_task(async function test() {
 
   // Since we need to test 'activemedia-blocked' attribute.
   Services.prefs.setBoolPref(PREF2, true)
   registerCleanupFunction(() => Services.prefs.clearUserPref(PREF2));
 
   // Add a new tab with a nice icon.
   let tab = BrowserTestUtils.addTab(gBrowser, "about:robots");
   await promiseBrowserLoaded(tab.linkedBrowser);
+  await BrowserTestUtils.waitForCondition(() => true,
+                                          "wait for loadFavicon to finish", 100);
 
   // Check that the tab has 'image' and 'iconLoadingPrincipal' attributes.
   ok(tab.hasAttribute("image"), "tab.image exists");
   ok(tab.hasAttribute("iconLoadingPrincipal"), "tab.iconLoadingPrincipal exists");
 
   tab.toggleMuteAudio();
   // Check that the tab has a 'muted' attribute.
   ok(tab.hasAttribute("muted"), "tab.muted exists");

--- a/browser/components/sessionstore/test/browser_label_and_icon.js
+++ b/browser/components/sessionstore/test/browser_label_and_icon.js
@@ -24,16 +24,18 @@ add_task(async function test_label_and_i
   await promiseRemoveTab(tab);
   browser = null;
 
   // Open a new tab to restore into.
   tab = BrowserTestUtils.addTab(gBrowser, "about:blank");
   ss.setTabState(tab, state);
   await promiseTabRestoring(tab);
 
+  await BrowserTestUtils.waitForCondition(() => true, "wait for loadFavicon to finish", 100);
+
   // Check that label and icon are set for the restoring tab.
   is(gBrowser.getIcon(tab), "chrome://browser/content/robot.ico", "icon is set");
   is(tab.label, "Gort! Klaatu barada nikto!", "label is set");
 
   let serhelper = Cc["@mozilla.org/network/serialization-helper;1"]
                     .getService(Ci.nsISerializationHelper);
   let serializedPrincipal = tab.getAttribute("iconLoadingPrincipal");
   let iconLoadingPrincipal = serhelper.deserializeObject(serializedPrincipal)

--- a/dom/security/test/general/test_bug1277803.xul
+++ b/dom/security/test/general/test_bug1277803.xul
@@ -15,16 +15,17 @@
   </body>
 
   <script type="application/javascript"><![CDATA[
     SimpleTest.requestCompleteLog();
     let Ci = Components.interfaces;
     let Cc = Components.classes;
     let Cu = Components.utils;
     let makeURI = Cu.import("resource://gre/modules/BrowserUtils.jsm", {}).BrowserUtils.makeURI;
+    SpecialPowers.pushPrefEnv({set: [["about.newtab.preload", false]]});
 
     const BASE_URI = "http://mochi.test:8888/chrome/dom/security/test/general/";
     const FAVICON_URI = BASE_URI + "favicon_bug1277803.ico";
     const LOADING_URI = BASE_URI + "bug1277803.html";
     let testWindow; //will be used to trigger favicon load
 
     let securityManager = Cc["@mozilla.org/scriptsecuritymanager;1"].
                           getService(Ci.nsIScriptSecurityManager);