diff --git a/lib/util.js b/lib/util.js
index <HASH>..<HASH> 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -476,7 +476,7 @@ var util = {
       } else if (callback && data.slice === 'function'
           && !isBuffer && typeof FileReader !== 'undefined') {
         // this might be a File/Blob
-        var index = 0, size = 1024 * 1024;
+        var index = 0, size = 1024 * 512;
         var reader = new FileReader();
         reader.onerror = function() {
           callback(new Error('Failed to read data.'));
Reduce chunk size to <I>kb