diff --git a/b2g/app/b2g.js b/b2g/app/b2g.js
index 44a209c0838..1af82f8df09 100644
--- a/b2g/app/b2g.js
+++ b/b2g/app/b2g.js
@@ -591,6 +591,13 @@ pref("browser.prompt.allowNative", false);
 // a restart is required to enable a new value.
 pref("network.activity.blipIntervalMilliseconds", 250);
 
+// By default we want the NetworkManager service to manage Gecko's offline
+// status for us according to the state of Wifi/cellular data connections.
+// In some environments, such as the emulator or hardware with other network
+// connectivity, this is not desireable, however, in which case this pref
+// can be flipped to false.
+pref("network.gonk.manage-offline-status", true);
+
 pref("jsloader.reuseGlobal", true);
 
 // Enable font inflation for browser tab content.
diff --git a/dom/system/gonk/NetworkManager.js b/dom/system/gonk/NetworkManager.js
index 1c43536184a..e6361e72e9e 100644
--- a/dom/system/gonk/NetworkManager.js
+++ b/dom/system/gonk/NetworkManager.js
@@ -27,7 +27,9 @@ const TOPIC_INTERFACE_REGISTERED     = "network-interface-registered";
 const TOPIC_INTERFACE_UNREGISTERED   = "network-interface-unregistered";
 const TOPIC_DEFAULT_ROUTE_CHANGED    = "network-default-route-changed";
 const TOPIC_MOZSETTINGS_CHANGED      = "mozsettings-changed";
+const TOPIC_PREF_CHANGED             = "nsPref:changed";
 const TOPIC_XPCOM_SHUTDOWN           = "xpcom-shutdown";
+const PREF_MANAGE_OFFLINE_STATUS     = "network.gonk.manage-offline-status";
 
 // TODO, get USB RNDIS interface name automatically.(see Bug 776212)
 const DEFAULT_USB_INTERFACE_NAME  = "rndis0";
@@ -109,9 +111,7 @@ function NetworkManager() {
 
   debug("Starting worker.");
   this.worker = new ChromeWorker("resource://gre/modules/net_worker.js");
-  this.worker.onmessage = function onmessage(event) {
-    this.handleWorkerMessage(event);
-  }.bind(this);
+  this.worker.onmessage = this.handleWorkerMessage.bind(this);
   this.worker.onerror = function onerror(event) {
     debug("Received error from worker: " + event.filename +
           ":" + event.lineno + ": " + event.message + "\n");
@@ -122,6 +122,14 @@ function NetworkManager() {
   // Callbacks to invoke when a reply arrives from the net_worker.
   this.controlCallbacks = Object.create(null);
 
+  try {
+    this._manageOfflineStatus =
+      Services.prefs.getBoolPref(PREF_MANAGE_OFFLINE_STATUS);
+  } catch(ex) {
+    // Ignore.
+  }
+  Services.prefs.addObserver(PREF_MANAGE_OFFLINE_STATUS, this, false);
+
   // Default values for internal and external interfaces.
   this._tetheringInterface = Object.create(null);
   this._tetheringInterface[TETHERING_TYPE_USB] = {externalInterface: DEFAULT_3G_INTERFACE_NAME,
@@ -224,6 +232,11 @@ NetworkManager.prototype = {
         let setting = JSON.parse(data);
         this.handle(setting.key, setting.value);
         break;
+      case TOPIC_PREF_CHANGED:
+        this._manageOfflineStatus =
+          Services.prefs.getBoolPref(PREF_MANAGE_OFFLINE_STATUS);
+        debug(PREF_MANAGE_OFFLINE_STATUS + " has changed to " + this._manageOfflineStatus);
+        break;
       case TOPIC_XPCOM_SHUTDOWN:
         Services.obs.removeObserver(this, TOPIC_XPCOM_SHUTDOWN);
         Services.obs.removeObserver(this, TOPIC_MOZSETTINGS_CHANGED);
@@ -279,6 +292,8 @@ NetworkManager.prototype = {
     debug("Network '" + network.name + "' unregistered.");
   },
 
+  _manageOfflineStatus: true,
+
   networkInterfaces: null,
 
   _preferredNetworkType: DEFAULT_PREFERRED_NETWORK_TYPE,
@@ -342,13 +357,13 @@ NetworkManager.prototype = {
   },
 
   handleWorkerMessage: function handleWorkerMessage(e) {
+    debug("NetworkManager received message from worker: " + JSON.stringify(e.data));
     let response = e.data;
     let id = response.id;
     let callback = this.controlCallbacks[id];
     if (callback) {
       callback.call(this, response);
     }
-    debug("NetworkManager received message from worker: " + JSON.stringify(e));
   },
 
   /**
@@ -405,7 +420,10 @@ NetworkManager.prototype = {
       }
       this.setDefaultRouteAndDNS(oldActive);
     }
-    Services.io.offline = !this.active;
+
+    if (this._manageOfflineStatus) {
+      Services.io.offline = !this.active;
+    }
   },
 
   setDefaultRouteAndDNS: function setDefaultRouteAndDNS(oldInterface) {
diff --git a/testing/marionette/marionette-actors.js b/testing/marionette/marionette-actors.js
index 1522ac3cb8b..49c70394157 100644
--- a/testing/marionette/marionette-actors.js
+++ b/testing/marionette/marionette-actors.js
@@ -41,6 +41,10 @@ Cu.import("resource://gre/modules/services-common/log4moz.js");
 let logger = Log4Moz.repository.getLogger("Marionette");
 logger.info('marionette-actors.js loaded');
 
+Services.prefs.setBoolPref("network.gonk.manage-offline-status", false);
+Services.io.manageOfflineStatus = false;
+Services.io.offline = false;
+
 // This is used to prevent newSession from returning before the telephony
 // API's are ready; see bug 792647.  This assumes that marionette-actors.js
 // will be loaded before the 'system-message-listener-ready' message
diff --git a/testing/marionette/marionette-listener.js b/testing/marionette/marionette-listener.js
index c87c86e342e..14bd0655ef2 100644
--- a/testing/marionette/marionette-listener.js
+++ b/testing/marionette/marionette-listener.js
@@ -60,8 +60,6 @@ let checkTimer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
  * If the actor returns an ID, we start the listeners. Otherwise, nothing happens.
  */
 function registerSelf() {
-  Services.io.manageOfflineStatus = false;
-  Services.io.offline = false;
   let msg = {value: winUtil.outerWindowID, href: content.location.href};
   let register = sendSyncMessage("Marionette:register", msg);