diff --git a/lib/millstone.js b/lib/millstone.js
index c2d41cf..01a59cf 100644
--- a/lib/millstone.js
+++ b/lib/millstone.js
@@ -443,26 +443,17 @@ function unzip(file, callback) {
                 path.basename(file, path.extname(file)) +
                 path.extname(name).toLowerCase()
             );
-            zf.readFile(name, function(err, buff) {
+            zf.copyFile(name, dest, function(err) {
                 if (err) return callback(err);
-                fs.open(dest, 'w', 0644, function(err, fd) {
-                    if (err) return callback(err);
-                    fs.write(fd, buff, 0, buff.length, null, function(err) {
-                        if (err) return callback(err);
-                        fs.close(fd, function(err) {
-                            if (err) return callback(err);
-                            remain--;
-                            if (!remain) {
-                                add_item_to_metafile(metafile,'unzipped_file',new_name,function(err) {
-                                    // ignore error from add_item_to_metafile
-                                    //if (err && env == 'development') console.error('[millstone] ' + err.message);
-                                    if (err) throw err;
-                                    callback(null, new_name);
-                                });
-                            }
-                        });
+                remain--;
+                if (!remain) {
+                    add_item_to_metafile(metafile,'unzipped_file',new_name,function(err) {
+                        // ignore error from add_item_to_metafile
+                        //if (err && env == 'development') console.error('[millstone] ' + err.message);
+                        if (err) throw err;
+                        callback(null, new_name);
                     });
-                });
+                }
             });
         }
     });
diff --git a/package.json b/package.json
index a3b2bd2..49028d9 100644
--- a/package.json
+++ b/package.json
@@ -20,7 +20,7 @@
         "generic-pool": "~2.1.1",
         "request": "2.x",
         "srs": "~0.4.6",
-        "zipfile": "~0.5.4",
+        "zipfile": "~0.5.5",
         "sqlite3": "2.x || 3.x",
         "mime": "~1.2.11",
         "mkdirp": "~0.5.0",