--- a/dom/media/test/manifest.js
+++ b/dom/media/test/manifest.js
@@ -547,17 +547,18 @@ var gSeekTests = [
 
 var gFastSeekTests = [
   { name:"gizmo.mp4", type:"video/mp4", keyframes:[0, 1.0, 2.0, 3.0, 4.0, 5.0 ] },
   // Note: Not all keyframes in the file are actually referenced in the Cues in this file.
   { name:"seek.webm", type:"video/webm", keyframes:[0, 0.8, 1.6, 2.4, 3.2]},
   // Note: the sync points are the points on both the audio and video streams
   // before the keyframes. You can't just assume that the keyframes are the sync
   // points, as the audio required for that sync point may be before the keyframe.
-  { name:"bug516323.indexed.ogv", type:"video/ogg", keyframes:[0, 0.46, 3.06] },
+  // We can only seek at the boundary of a page index. see bug 1289438.
+  { name:"bug516323.indexed.ogv", type:"video/ogg", keyframes:[0, 3.06] },
 ];
 
 function IsWindows8OrLater() {
   var re = /Windows NT (\d.\d)/;
   var winver = manifestNavigator().userAgent.match(re);
   return winver && winver.length == 2 && parseFloat(winver[1]) >= 6.2;
 }