diff --git a/browser/base/content/tab-content.js b/browser/base/content/tab-content.js
index c8f39ee8f..a99bd5d8b 100644
--- a/browser/base/content/tab-content.js
+++ b/browser/base/content/tab-content.js
@@ -11,6 +11,9 @@ Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://gre/modules/Services.jsm");
 Cu.import("resource://gre/modules/ExtensionContent.jsm");
 
+const g104FxForcePref = "tenfourfox.reader.force-enable"; // TenFourFox issue 583
+Cu.import("resource://gre/modules/Preferences.jsm");
+
 XPCOMUtils.defineLazyModuleGetter(this, "E10SUtils",
   "resource:///modules/E10SUtils.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "BrowserUtils",
@@ -254,6 +257,7 @@ AboutPrivateBrowsingListener.init(this);
 var AboutReaderListener = {
 
   _articlePromise: null,
+  _alwaysAllowReaderMode: true, // TenFourFox issue 583
 
   init: function() {
     addEventListener("AboutReaderContentLoaded", this, false, true);
@@ -262,6 +266,17 @@ var AboutReaderListener = {
     addEventListener("pagehide", this, false);
     addMessageListener("Reader:ParseDocument", this);
     addMessageListener("Reader:PushState", this);
+    Services.prefs.addObserver(g104FxForcePref, this, false);
+  },
+
+  // TenFourFox issue 583
+  uninit: function() {
+    Services.prefs.removeObserver(g104FxForcePref, this, false);
+  },
+  observe: function(subject, topic, data) { // jshint ignore:line
+    if (topic === "nsPref:changed") {
+      this._alwaysAllowReaderMode = Preferences.get(g104FxForcePref, true);
+    }
   },
 
   receiveMessage: function(message) {
@@ -357,6 +372,17 @@ var AboutReaderListener = {
 
   onPaintWhenWaitedFor: function(forceNonArticle) {
     this.cancelPotentialPendingReadabilityCheck();
+
+    // TenFourFox issue 583
+    // If we are always allowing reader mode, don't bother spending any time
+    // processing the page. But don't let just everything through.
+    if (!this.isAboutReader) {
+      if (this._alwaysAllowReaderMode && !(content.document.documentURI.startsWith("about:"))) {
+        sendAsyncMessage("Reader:UpdateReaderButton", { isArticle: true });
+        return;
+      }
+    }
+
     // Only send updates when there are articles; there's no point updating with
     // |false| all the time.
     if (ReaderMode.isProbablyReaderable(content.document)) {
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index c8c08aa4b..a7ace746c 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -1041,9 +1041,6 @@ pref("dom.disable_window_open_feature.status",      true);
 
 pref("dom.allow_scripts_to_close_windows",          false);
 
-// TenFourFox issue 463
-pref("tenfourfox.dom.requestIdleCallback.enabled",  false);
-
 pref("dom.require_user_interaction_for_beforeunload", true);
 
 pref("dom.disable_open_during_load",                false);
@@ -5159,7 +5156,13 @@ pref("toolkit.pageThumbs.minHeight", 0);
 // when the page is reloaded. To turn this feature off, just set the limit to 0.
 pref("prompts.authentication_dialog_abuse_limit", 3);
 
+// TenFourFox issue 463
+pref("tenfourfox.dom.requestIdleCallback.enabled",  false);
+
 pref("tenfourfox.adblock.enabled", false);
 pref("tenfourfox.adblock.logging.enabled", false);
 pref("tenfourfox.dom.forms.date", true);
 pref("tenfourfox.dom.forms.time", true);
+
+// TenFourFox issue 583
+pref("tenfourfox.reader.force-enable", true);