diff --git a/clone.js b/clone.js
index 028356c..dff3cc8 100644
--- a/clone.js
+++ b/clone.js
@@ -2,12 +2,16 @@
 
 module.exports = clone
 
+var getPrototypeOf = Object.getPrototypeOf || function (obj) {
+  return obj.__proto__
+}
+
 function clone (obj) {
   if (obj === null || typeof obj !== 'object')
     return obj
 
   if (obj instanceof Object)
-    var copy = { __proto__: obj.__proto__ }
+    var copy = { __proto__: getPrototypeOf(obj) }
   else
     var copy = Object.create(null)
 
diff --git a/polyfills.js b/polyfills.js
index a5808d2..bc6178f 100644
--- a/polyfills.js
+++ b/polyfills.js
@@ -132,7 +132,7 @@ function patch (fs) {
     }
 
     // This ensures `util.promisify` works as it does for native `fs.read`.
-    read.__proto__ = fs$read
+    if (Object.setPrototypeOf) Object.setPrototypeOf(read, fs$read)
     return read
   })(fs.read)