diff --git a/lib/firmata.js b/lib/firmata.js
index 2fa77bc..6c2fcb6 100644
--- a/lib/firmata.js
+++ b/lib/firmata.js
@@ -1,4 +1,5 @@
-require("es6-shim");
+var assign = require("object-assign");
+
 /**
  * @author Julian Gautier
  */
@@ -366,7 +367,7 @@ var Board = function(port, options, callback) {
   }
 
   var board = this;
-  var settings = Object.assign({}, defaults, options);
+  var settings = assign({}, defaults, options);
 
   var ready = function() {
     this.emit("ready");
diff --git a/package.json b/package.json
index 41688ad..4558fb1 100644
--- a/package.json
+++ b/package.json
@@ -25,7 +25,7 @@
   },
   "dependencies": {
     "browser-serialport": "*",
-    "es6-shim": "^0.20.2",
+    "object-assign": "^1.0.0",
     "serialport": ">=0.7.5"
   },
   "optionalDependencies": {},