diff --git a/mozilla/browser/app/profile/firefox.js b/mozilla/browser/app/profile/firefox.js
index a5db9cb793b..03658f6c70e 100644
--- a/mozilla/browser/app/profile/firefox.js
+++ b/mozilla/browser/app/profile/firefox.js
@@ -71,14 +71,24 @@ pref("extensions.ignoreMTimeChanges", false);
 pref("extensions.logging.enabled", false);
 
 // App-specific update preferences
-pref("app.update.enabled", false);               // Whether or not app updates are enabled
 
-// Whether or not automated background app updates are enabled.
-pref("app.update.autoInstallEnabled", true);
-// If automatic download is enabled, whether or not the Update system should 
-// automatically install the downloaded updates or just download them and prompt
-// the user to install.
-pref("app.update.autoInstallMode", 0);
+// Whether or not app updates are enabled
+pref("app.update.enabled", false);               
+
+// Defines how the Application Update Service notifies the user about updates:
+//
+// AUM Set to:        Minor Releases:     Major Releases:
+// 0                  download no prompt  download no prompt
+// 1                  download no prompt  download no prompt if no incompatibilities
+// 2                  download no prompt  prompt
+// 3                  prompt              prompt
+//
+// See chart in nsUpdateService.js.in for more details
+//
+pref("app.update.mode", 1);
+
+// If set to true, the Update Service will present no UI for any event.
+pref("app.update.silent", false);
 
 // XXX these prefs and others like them are distribution specific and should move 
 //     into chrome://browser
diff --git a/mozilla/browser/base/content/utilityOverlay.js b/mozilla/browser/base/content/utilityOverlay.js
index 69bcf4a3a26..52283ed1570 100644
--- a/mozilla/browser/base/content/utilityOverlay.js
+++ b/mozilla/browser/base/content/utilityOverlay.js
@@ -459,11 +459,18 @@ function buildHelpMenu()
   var um = 
       Components.classes["@mozilla.org/updates/update-manager;1"].
       getService(Components.interfaces.nsIUpdateManager);
-  var activeUpdate = um.activeUpdate;
+
+  // Disable the UI if the update enabled pref has been locked by the 
+  // administrator or if we cannot update for some other reason
+  var checkForUpdates = document.getElementById("checkForUpdates");
+  var canUpdate = updates.canUpdate;
+  checkForUpdates.setAttribute("disabled", !canUpdate);
+  if (!canUpdate)
+    return; 
 
   var strings = document.getElementById("bundle_browser");
-  
   var label = strings.getString("updates_checkForUpdates");
+  var activeUpdate = um.activeUpdate;
   if (activeUpdate) {
     if (updates.isDownloading) {
       if (activeUpdate.name) {
@@ -483,15 +490,10 @@ function buildHelpMenu()
     }
   }
   
-  var checkForUpdates = document.getElementById("checkForUpdates");
   checkForUpdates.label = label;
   if (um.activeUpdate && updates.isDownloading)
     checkForUpdates.setAttribute("loading", "true");
   else
     checkForUpdates.removeAttribute("loading");
-    
-  // Disable the UI if the update enabled pref has been locked by the 
-  // administrator.
-  checkForUpdates.disabled = gPrefService.prefIsLocked("app.update.enabled");
 }
 
diff --git a/mozilla/browser/components/preferences/advanced.js b/mozilla/browser/components/preferences/advanced.js
index 32d82a509cd..001a85fac77 100644
--- a/mozilla/browser/components/preferences/advanced.js
+++ b/mozilla/browser/components/preferences/advanced.js
@@ -95,6 +95,13 @@ var gAdvancedPane = {
   {
     var preference = document.getElementById("app.update.enabled");
     document.getElementById("enableAutoInstall").disabled = !preference.value;
+
+    var aus = 
+        Components.classes["@mozilla.org/updates/update-service;1"].
+        getService(Components.interfaces.nsIApplicationUpdateService);
+    var checkNowButton = document.getElementById("checkNowButton");
+    checkNowButton.disabled = !aus.canUpdate;
+    
     this.updateAutoInstallUI();
     return undefined;
   },
@@ -129,8 +136,9 @@ var gAdvancedPane = {
     var features = "chrome,centerscreen,dialog,titlebar";
     const URI_EXTENSION_UPDATE_DIALOG = 
       "chrome://mozapps/content/extensions/update.xul";
-    var ww = Components.classes["@mozilla.org/embedcomp/window-watcher;1"]
-                        .getService(Components.interfaces.nsIWindowWatcher);
+    var ww = 
+        Components.classes["@mozilla.org/embedcomp/window-watcher;1"].
+        getService(Components.interfaces.nsIWindowWatcher);
     ww.openWindow(window, URI_EXTENSION_UPDATE_DIALOG, "", features, ary);  
   },
   
diff --git a/mozilla/browser/components/preferences/advanced.xul b/mozilla/browser/components/preferences/advanced.xul
index ba1adb16c3d..00843333c55 100644
--- a/mozilla/browser/components/preferences/advanced.xul
+++ b/mozilla/browser/components/preferences/advanced.xul
@@ -59,7 +59,7 @@
       <preference id="general.smoothScroll"            name="general.smoothScroll"            type="bool"/>
       <preference id="app.update.enabled"              name="app.update.enabled"              type="bool"/>
       <preference id="app.update.autoInstallEnabled"   name="app.update.autoInstallEnabled"   type="bool"/>
-      <preference id="app.update.autoInstallMode"      name="app.update.autoInstallMode"      type="int"/>
+      <preference id="app.update.mode"                 name="app.update.mode"                 type="int"/>
       <preference id="extensions.update.autoUpdateEnabled"
                   name="extensions.update.autoUpdateEnabled"
                   type="bool"/>
@@ -142,7 +142,7 @@
                           accesskey="&enableAutoInstall.accesskey;"
                           preference="app.update.autoInstallEnabled"
                           onpreferenceread="return gAdvancedPane.updateAutoInstallUI();"/>
-                <radiogroup id="autoInstallMode" preference="app.update.autoInstallMode">
+                <radiogroup id="autoInstallMode" preference="app.update.mode">
                   <grid class="indent">
                     <columns>
                       <column/>
@@ -161,7 +161,8 @@
                 </radiogroup>
                 <separator class="thin"/>
                 <hbox>
-                  <button label="&checkNow.label;" accesskey="&appCheckNow.accesskey;"
+                  <button id="checkNowButton" 
+                          label="&checkNow.label;" accesskey="&appCheckNow.accesskey;"
                           oncommand="gAdvancedPane.checkForUpdates();"
                           preference="app.update.enabled"/>
                   <button label="&showUpdates.label;" accesskey="&showUpdates.accesskey;"
diff --git a/mozilla/toolkit/mozapps/update/content/history.js b/mozilla/toolkit/mozapps/update/content/history.js
index 5a527a1ee5a..86f8757561e 100644
--- a/mozilla/toolkit/mozapps/update/content/history.js
+++ b/mozilla/toolkit/mozapps/update/content/history.js
@@ -61,6 +61,8 @@ var gUpdateHistory = {
         
         var element = document.createElementNS(NS_XUL, "update");
         this._view.appendChild(element);
+        if (!update.name)
+          continue;
         element.name = update.name;
         element.type = bundle.getString("updateType_" + update.type);
         element.installDate = this._formatDate(update.installDate);
diff --git a/mozilla/toolkit/mozapps/update/content/updates.js b/mozilla/toolkit/mozapps/update/content/updates.js
index 1e1225431d9..9da929df2ed 100755
--- a/mozilla/toolkit/mozapps/update/content/updates.js
+++ b/mozilla/toolkit/mozapps/update/content/updates.js
@@ -133,7 +133,7 @@ var gUpdates = {
    * the function call to the selected page.
    */
   onWizardFinish: function() {
-    var pageid = gUpdates.wiz.currentPage.pageid;
+    var pageid = document.documentElement.currentPage.pageid;
     if ("onWizardFinish" in this._pages[pageid])
       this._pages[pageid].onWizardFinish();
   },
@@ -143,11 +143,24 @@ var gUpdates = {
    * the function call to the selected page.
    */
   onWizardCancel: function() {
-    var pageid = gUpdates.wiz.currentPage.pageid;
+    var pageid = document.documentElement.currentPage.pageid;
     if ("onWizardCancel" in this._pages[pageid])
       this._pages[pageid].onWizardCancel();
   },
   
+  /**
+   * Called when the user presses the "Next" button on the wizard, dispatches
+   * the function call to the selected page.
+   */
+  onWizardNext: function() {
+    var cp = document.documentElement.currentPage;
+    if (!cp)  
+      return;
+    var pageid = cp.pageid;
+    if ("onWizardNext" in this._pages[pageid])
+      this._pages[pageid].onWizardNext();
+  },
+  
   /**
    * The checking process that spawned this update UI. There are two types:
    * SRCEVT_FOREGROUND:
@@ -276,9 +289,6 @@ var gUpdates = {
   setUpdate: function(update) {
     this.update = update;
     this.update.QueryInterface(Components.interfaces.nsIWritablePropertyBag);
-    var p = this.update.selectedPatch;
-    if (p)
-      p.QueryInterface(Components.interfaces.nsIWritablePropertyBag);
   },
   
   /**
@@ -493,8 +503,16 @@ var gUpdatesAvailablePage = {
     // If we were invoked from a background update check, automatically show 
     // the additional details the user may need to make this decision since 
     // they did not consciously make the decision to check. 
-    if (gUpdates.sourceEvent == SRCEVT_BACKGROUND)
-      this.onShowMoreDetails();
+    // if (gUpdates.sourceEvent == SRCEVT_BACKGROUND)
+    // This is ridiculous... always show the additional info.
+    this.onShowMoreDetails();
+      
+    try {
+      gUpdates.update.getProperty("licenseAccepted");
+    }
+    catch (e) {
+      gUpdates.update.setProperty("licenseAccepted", "false");
+    }
     
     var downloadNow = document.getElementById("downloadNow");
     downloadNow.focus();
@@ -601,6 +619,10 @@ var gLicensePage = {
    */
   onWizardNext: function() {
     gUpdates.update.setProperty("licenseAccepted", "true");
+    var um = 
+        Components.classes["@mozilla.org/updates/update-manager;1"].
+        getService(Components.interfaces.nsIUpdateManager);
+    um.saveUpdates();
   },
   
   /**
@@ -885,10 +907,8 @@ var gDownloadingPage = {
         Components.classes["@mozilla.org/updates/update-manager;1"].
         getService(Components.interfaces.nsIUpdateManager);
     var activeUpdate = um.activeUpdate;
-    if (activeUpdate) {
+    if (activeUpdate)
       gUpdates.setUpdate(activeUpdate);
-      this._togglePausedState(!updates.isDownloading);
-    }
     
     if (!gUpdates.update) {
       LOG("UI:DownloadingPage.Progress", "no valid update to download?!");
@@ -911,6 +931,9 @@ var gDownloadingPage = {
       updates.addDownloadListener(this);
     }
     
+    if (activeUpdate)
+      this._setUIState(!updates.isDownloading);
+    
     gUpdates.wiz.getButton("back").disabled = true;
     var cancelButton = gUpdates.wiz.getButton("cancel");
     cancelButton.label = gUpdates.strings.getString("closeButtonLabel");
@@ -954,24 +977,28 @@ var gDownloadingPage = {
    * @param   paused
    *          Whether or not the download is paused
    */
-  _togglePausedState: function(paused) {
+  _setUIState: function(paused) {
     var u = gUpdates.update;
     var p = u.selectedPatch.QueryInterface(Components.interfaces.nsIPropertyBag);
+    var status = p.getProperty("status");
     if (paused) {
       this._oldStatus = this._downloadStatus.textContent;
       this._oldMode = this._downloadProgress.mode;
       this._oldProgress = parseInt(this._downloadProgress.progress);
       this._downloadName.value = gUpdates.strings.getFormattedString(
         "pausedName", [u.name]);
-      this._setStatus(p.getProperty("status"));
+      if (status)
+        this._setStatus(status);
       this._downloadProgress.mode = "normal";
-      
       this._pauseButton.label = gUpdates.strings.getString("pauseButtonResume");
     }
     else {
       this._downloadName.value = gUpdates.strings.getFormattedString(
         "downloadingPrefix", [u.name]);
-      this._setStatus(this._oldStatus || p.getProperty("status"));
+      if (this._oldStatus)
+        this._setStatus(this._oldStatus);
+      else if (status)
+        this._setStatus(status);
       this._downloadProgress.value = 
         this._oldProgress || parseInt(p.getProperty("progress"));
       this._downloadProgress.mode = this._oldMode || "normal";
@@ -990,6 +1017,7 @@ var gDownloadingPage = {
       updates.downloadUpdate(gUpdates.update, false);
     else {
       var patch = gUpdates.update.selectedPatch;
+      patch.QueryInterface(Components.interfaces.nsIWritablePropertyBag);
       patch.setProperty("status", 
         gUpdates.strings.getFormattedString("pausedStatus", 
           [this.statusFormatter.progress]));
@@ -998,7 +1026,7 @@ var gDownloadingPage = {
     this._paused = !this._paused;
     
     // Update the UI
-    this._togglePausedState(this._paused);
+    this._setUIState(this._paused);
   },
   
   /** 
@@ -1072,6 +1100,7 @@ var gDownloadingPage = {
         "/" + maxProgress);
 
     var p = gUpdates.update.selectedPatch;
+    p.QueryInterface(Components.interfaces.nsIWritablePropertyBag);
     p.setProperty("progress", Math.round(100 * (progress/maxProgress)));
     p.setProperty("status", 
       this.statusFormatter.formatStatus(progress, maxProgress));
@@ -1081,7 +1110,9 @@ var gDownloadingPage = {
     this._pauseButton.disabled = false;
     var name = gUpdates.strings.getFormattedString("downloadingPrefix", [gUpdates.update.name]);
     this._downloadName.value = name;
-    this._setStatus(p.getProperty("status"));
+    var status = p.getProperty("status");
+    if (status)
+      this._setStatus(status);
   },
   
   /** 
diff --git a/mozilla/toolkit/mozapps/update/content/updates.xul b/mozilla/toolkit/mozapps/update/content/updates.xul
index 8068ffcaf71..e0697ee8d4d 100755
--- a/mozilla/toolkit/mozapps/update/content/updates.xul
+++ b/mozilla/toolkit/mozapps/update/content/updates.xul
@@ -54,6 +54,7 @@
         windowtype="Update:Wizard" style="width: 36em;"
         onwizardfinish="gUpdates.onWizardFinish();"
         onwizardcancel="gUpdates.onWizardCancel();"
+        onwizardnext="gUpdates.onWizardNext();"        
         onload="gUpdates.onLoad();">
 
   <script type="application/x-javascript" src="chrome://mozapps/content/update/updates.js"/>
@@ -125,8 +126,7 @@
   
   <wizardpage id="license" pageid="license" next="downloading"
               object="gLicensePage" label="&license.title;"
-              onpageshow="gLicensePage.onPageShow();"
-              onwizardnext="gLicensePage.onWizardNext();">
+              onpageshow="gLicensePage.onPageShow();">
     <label>&license.intro;</label>
     <separator class="thin"/>
     <license id="licenseContent" flex="1"/>
diff --git a/mozilla/toolkit/mozapps/update/public/nsIUpdateService.idl b/mozilla/toolkit/mozapps/update/public/nsIUpdateService.idl
index 3c2efbb16ed..404a56d3e16 100644
--- a/mozilla/toolkit/mozapps/update/public/nsIUpdateService.idl
+++ b/mozilla/toolkit/mozapps/update/public/nsIUpdateService.idl
@@ -306,11 +306,6 @@ interface nsIUpdateChecker : nsISupports
    *          A value representing the set of checks to stop doing.
    */
   void stopChecking(in unsigned short duration);
-
-  /**
-   * Whether or not this Checker can perform update checking.
-   */
-  readonly attribute boolean enabled;
 };
 
 [scriptable, uuid(9849c4bf-5197-4d22-baa8-e3b44a1703d2)]
@@ -364,6 +359,13 @@ interface nsIApplicationUpdateService : nsISupports
    * Whether or not there is an download happening at the moment.
    */
   readonly attribute boolean isDownloading;
+
+  /**
+   * Whether or not the Update Service can download and install updates.
+   * This is a function of whether or not the current user has access 
+   * privileges to the install directory.
+   */
+  readonly attribute boolean canUpdate;
 };
 
 [scriptable, uuid(fede66a9-9f96-4507-a22a-775ee885577e)]
diff --git a/mozilla/toolkit/mozapps/update/src/nsUpdateService.js.in b/mozilla/toolkit/mozapps/update/src/nsUpdateService.js.in
index 259bc65c728..74d661102d1 100644
--- a/mozilla/toolkit/mozapps/update/src/nsUpdateService.js.in
+++ b/mozilla/toolkit/mozapps/update/src/nsUpdateService.js.in
@@ -37,22 +37,13 @@
  * ***** END LICENSE BLOCK ***** */
 
 const PREF_APP_UPDATE_ENABLED             = "app.update.enabled";
-const PREF_APP_UPDATE_AUTOINSTALL_ENABLED = "app.update.autoInstallEnabled";
-// Defines the notification behavior when updates are encountered
-//
-// 0 = download and install all updates (including major versions, provided
-//     no addons are made incompatible)
-// 1 = download and install minor (security) updates
-// 2 = ask before doing anything
-//
-const PREF_APP_UPDATE_AUTOINSTALL_MODE    = "app.update.autoInstallMode";
+const PREF_APP_UPDATE_MODE                = "app.update.mode";
+const PREF_APP_UPDATE_SILENT              = "app.update.silent";
 const PREF_APP_UPDATE_INTERVAL            = "app.update.interval";
 const PREF_APP_UPDATE_TIMER               = "app.update.timer";
 const PREF_APP_UPDATE_LOG_BRANCH          = "app.update.log.";
-
 const PREF_APP_UPDATE_URL                 = "app.update.url";
 const PREF_APP_UPDATE_URL_OVERRIDE        = "app.update.url.override";
-
 const PREF_UPDATE_LASTUPDATETIME_FMT      = "app.update.lastUpdateTime.%ID%";
 const PREF_APP_EXTENSIONS_VERSION         = "app.extensions.version";
 
@@ -70,6 +61,7 @@ const FILE_UPDATE_ARCHIVE = "update.mar";
 const FILE_UPDATE_INFO    = "update.info";
 const FILE_UPDATES_DB     = "updates.xml";
 const FILE_UPDATE_ACTIVE  = "active-update.xml";
+const FILE_PERMS_TEST     = "update.test";
 
 const MODE_RDONLY   = 0x01;
 const MODE_WRONLY   = 0x02;
@@ -425,28 +417,40 @@ UpdatePrompt.prototype = {
    * See nsIUpdateService.idl
    */
   showUpdateAvailable: function(parent, update) {
-    this._showUI(parent, URI_UPDATE_PROMPT_DIALOG, null, "Update:Wizard", update);
+    if (this._enabled) {
+      this._showUI(parent, URI_UPDATE_PROMPT_DIALOG, null, "Update:Wizard", 
+                   update);
+    }
   },
   
   /**
    * See nsIUpdateService.idl
    */
   showUpdateDownloaded: function(parent, update) {
-    this._showUI(parent, URI_UPDATE_PROMPT_DIALOG, null, "Update:Wizard", update);
+    if (this._enabled) {
+      this._showUI(parent, URI_UPDATE_PROMPT_DIALOG, null, "Update:Wizard", 
+                   update);
+    }
   },
   
   /**
    * See nsIUpdateService.idl
    */
   showUpdateInstalled: function(update) {
-    this._showUI(null, URI_UPDATE_PROMPT_DIALOG, "modal", "Update:Wizard", update);
+    if (this._enabled) {
+      this._showUI(null, URI_UPDATE_PROMPT_DIALOG, "modal", "Update:Wizard", 
+                   update);
+    }
   },
   
   /**
    * See nsIUpdateService.idl
    */
   showUpdateError: function(update) {
-    this._showUI(null, URI_UPDATE_PROMPT_DIALOG, "modal", "Update:Wizard", update);
+    if (this._enabled) {
+      this._showUI(null, URI_UPDATE_PROMPT_DIALOG, "modal", "Update:Wizard", 
+                   update);
+    }
   },
   
   /**
@@ -456,6 +460,13 @@ UpdatePrompt.prototype = {
     this._showUI(parent, URI_UPDATE_HISTORY_DIALOG, "modal", "Update:History", null);
   },
   
+  /**
+   * Whether or not we are enabled (i.e. not in Silent mode)
+   */
+  get _enabled() {
+    return !getPref("getBoolPref", PREF_APP_UPDATE_SILENT, false);
+  },
+  
   /**
    * Show the Update Checking UI
    * @param   parent
@@ -689,15 +700,17 @@ UpdateService.prototype = {
     // The outcome we follow is determined as follows:
     // 
     // Update Type      Mode      Incompatible    Outcome
-    // Major            0         No              Auto Install
-    // Major            0         Yes             Notify and Confirm
-    // Major            1         Yes or No       Notify and Confirm
+    // Major            0         Yes or No       Auto Install
+    // Major            1         No              Auto Install
+    // Major            1         Yes             Notify and Confirm
     // Major            2         Yes or No       Notify and Confirm
-    // Minor            0         No              Auto Install
-    // Minor            0         Yes             Notify and Confirm
+    // Major            3         Yes or No       Notify and Confirm
+    // Minor            0         Yes or No       Auto Install
     // Minor            1         No              Auto Install
     // Minor            1         Yes             Notify and Confirm
-    // Minor            2         Yes or No       Notify and Confirm
+    // Minor            2         No              Auto Install
+    // Minor            2         Yes             Notify and Confirm
+    // Minor            3         Yes or No       Notify and Confirm
     //
     // In addition, if there is a license associated with an update, regardless
     // of type it must be agreed to. 
@@ -705,18 +718,30 @@ UpdateService.prototype = {
     // If app.update.enabled is set to false, an update check is not performed
     // at all, and so none of the decision making above is entered into.
     //
-    if (update.licenseURL)
+    update.QueryInterface(Components.interfaces.nsIPropertyBag);
+    var licenseAccepted = update.getProperty("licenseAccepted") == "true";
+    if (update.licenseURL && !licenseAccepted)
       return true;
     
     var updateEnabled = getPref("getBoolPref", PREF_APP_UPDATE_ENABLED, true);
     if (!updateEnabled)
       return false;
       
-    var mode = getPref("getIntPref", PREF_APP_UPDATE_AUTOINSTALL_MODE, 0);
-    var compatible = isCompatible(update);
-    if ((update.type == "major" && (mode == 0)) ||
-        (update.type == "minor" && (mode == 0 || mode == 1)))
-      return !compatible;
+    switch (getPref("getIntPref", PREF_APP_UPDATE_MODE, 1)) {
+    case 0:
+      // Mode 0 is do not prompt regardless of incompatibilities
+      return false;
+    case 1:
+      // Mode 1 is do not prompt only if there are no incompatibilities
+      // releases
+      return !isCompatible(update);
+    case 2:
+      // Mode 2 is do not prompt only if there are no incompatibilities for 
+      // minor updates only
+      if (update.type == "minor")
+        return !isCompatible(update);
+    }
+    // Mode 3 is prompt, regardless.
     return true;
   },
   
@@ -784,6 +809,24 @@ UpdateService.prototype = {
     return this._backgroundChecker;
   },
   
+  /**
+   * See nsIUpdateService.idl
+   */
+  get canUpdate() {
+    try {
+      var file = getFile(KEY_APPDIR, [FILE_PERMS_TEST]);
+      if (!file.exists()) {
+        file.create(nsILocalFile.NORMAL_FILE_TYPE, PERMS_FILE);
+        file.remove(false);
+      }
+    }
+    catch (e) {
+      // No write privileges to install directory
+      return false;
+    }
+    return true;
+  },
+  
   /**
    * See nsIUpdateService.idl
    */
@@ -921,18 +964,15 @@ UpdateManager.prototype = {
     this._ensureActiveUpdate();
   },
 
-  _loadedActiveUpdate: false,
-  
   /**
    * Ensure that the Active Update file is loaded.
    */
   _ensureActiveUpdate: function() {
-    if (!this._loadedActiveUpdate) {
+    if (!this._activeUpdate) {
       var updates = this._loadXMLFileIntoArray(getFile(KEY_APPDIR, 
         [FILE_UPDATE_ACTIVE]));
       if (updates.length > 0)
         this._activeUpdate = updates[0];
-      this._loadedActiveUpdate = true;
     }
   },
   
@@ -962,7 +1002,7 @@ UpdateManager.prototype = {
   set activeUpdate(activeUpdate) {
     this._ensureActiveUpdate();
     if (!activeUpdate)
-      this._updates = [this._activeUpdate].concat(this._updates);
+      this._addUpdate(this._activeUpdate);
     this._activeUpdate = activeUpdate;
     if (!activeUpdate) {
       // If |activeUpdate| is null, we have updated both lists - the active list
@@ -984,7 +1024,32 @@ UpdateManager.prototype = {
   },
   
   /**
-   *
+   * Add an update to the Updates list. If the item already exists in the list,
+   * replace the existing value with the new value.
+   * @param   update
+   *          The nsIUpdate object to add.
+   */
+  _addUpdate: function(update) {
+    if (this._updates) {
+      for (var i = 0; i < this._updates.length; ++i) {
+        if (this._updates[i].version == update.version) {
+          // Replace the existing entry with the new value, updating
+          // all metadata.
+          this._updates[i] = update;
+          return;
+        }
+      }
+    }
+    // Otherwise add it to the front of the list.
+    this._updates = [this._activeUpdate].concat(this._updates);
+  },
+  
+  /**
+   * Serializes an array of updates to an XML file
+   * @param   updates
+   *          An array of nsIUpdate objects
+   * @param   file
+   *          The nsIFile object to serialize to
    */
   _writeUpdatesToXMLFile: function(updates, file) {
     var fos = Components.classes["@mozilla.org/network/safe-file-output-stream;1"]
@@ -1256,7 +1321,7 @@ Update.prototype = {
     
     for (var p in this._properties) {
       if (this._properties[p].present)
-        patch.setAttribute(p, this._properties[p].data);
+        update.setAttribute(p, this._properties[p].data);
     }
     
     for (var i = 0; i < this.patchCount; ++i)
@@ -1502,8 +1567,11 @@ Checker.prototype = {
    * See nsIUpdateService.idl
    */
   get enabled() {
+    var aus = 
+        Components.classes["@mozilla.org/updates/update-service;1"].
+        getService(Components.interfaces.nsIApplicationUpdateService);
     var enabled = getPref("getBoolPref", PREF_APP_UPDATE_ENABLED, true) && 
-                  this._enabled;
+                  aus.canUpdate && this._enabled;
     return enabled;
   },
   
@@ -1867,6 +1935,7 @@ Downloader.prototype = {
     var shouldShowPrompt = false;
     var deleteActiveUpdate = false;
     const NS_BINDING_ABORTED = 0x804b0002;
+    const NS_ERROR_ABORT = 0x80004004;
     if (Components.isSuccessCode(status)) {
       if (this._verifyDownload()) {
         state = STATE_PENDING;
@@ -1908,7 +1977,8 @@ Downloader.prototype = {
         cleanUpUpdatesDir();
       }
     }
-    else if (status != NS_BINDING_ABORTED) {
+    else if (status != NS_BINDING_ABORTED &&
+             status != NS_ERROR_ABORT) {
       LOG("Downloader", "onStopRequest: Non-verification failure");
       // Some sort of other failure, log this in the |statusText| property
       state = STATE_FAILED;