--- a/content/html/content/src/HTMLMediaElement.cpp
+++ b/content/html/content/src/HTMLMediaElement.cpp
@@ -1057,23 +1057,16 @@ void HTMLMediaElement::UpdatePreloadActi
       }
     } else {
       // Use the suggested "missing value default" of "metadata", or the value
       // specified by the media.preload.default, if present.
       nextAction = static_cast<PreloadAction>(preloadDefault);
     }
   }
 
-  if ((mBegun || mIsRunningSelectResource) && nextAction < mPreloadAction) {
-    // We've started a load or are already downloading, and the preload was
-    // changed to a state where we buffer less. We don't support this case,
-    // so don't change the preload behaviour.
-    return;
-  }
-
   mPreloadAction = nextAction;
   if (nextAction == HTMLMediaElement::PRELOAD_ENOUGH) {
     if (mSuspendedForPreloadNone) {
       // Our load was previouly suspended due to the media having preload
       // value "none". The preload value has changed to preload:auto, so
       // resume the load.
       ResumeLoad(PRELOAD_ENOUGH);
     } else {

--- a/content/media/test/test_preload_actions.html
+++ b/content/media/test/test_preload_actions.html
@@ -381,44 +381,16 @@ var tests = [
       v.addEventListener("loadedmetadata", function(e){v._gotLoadedMetaData = true;}, false);
       v.addEventListener("loadeddata", this.loadeddata, false);
       v.src = test.name; // Causes implicit load.
       document.body.appendChild(v);
     },
 
     name: "test11",
   },
-  /*{
-    // 12. Change preload value from auto to metadata after load started,
-    // should still do full load, should not halt after metadata only.
-    // disable this test since the spec is no longer found in the document
-    // http://dev.w3.org/html5/spec-preview/media-elements.html
-    canplaythrough:
-    function(e) {
-      var v = e.target;
-      is(v._gotLoadedMetaData, true, "(12) Must get loadedmetadata.");
-      is(v._gotLoadStart, true, "(12) Must get loadstart.");
-      maybeFinish(v, 12);
-    },
-
-    setup:
-    function(v) {
-      v._gotLoadStart = false;
-      v._gotLoadedMetaData = false;
-      v.preload = "auto";
-      v.addEventListener("loadstart", function(e){v._gotLoadStart = true;}, false);
-      v.addEventListener("loadedmetadata", function(e){v._gotLoadedMetaData = true;}, false);
-      v.addEventListener("canplaythrough", this.canplaythrough, false);
-      v.src = test.name; // Causes implicit load.
-      document.body.appendChild(v);
-      v.preload = "metadata";
-    },
-
-    name: "test12",
-  },*/
   {
     // 13. Change preload value from auto to none after specifying a src
     // should load according to preload none, no buffering should have taken place
     suspend:
     function(e) {
       var v = e.target;
       is(v._gotLoadStart, true, "(13) Must get loadstart.");
       is(v._gotLoadedMetaData, false, "(13) Must not get loadedmetadata.");