diff --git a/src/CustomElements/boot.js b/src/CustomElements/boot.js
index 14e4bb7dc..2eeb40584 100644
--- a/src/CustomElements/boot.js
+++ b/src/CustomElements/boot.js
@@ -15,27 +15,6 @@ var initializeModules = scope.initializeModules;
 
 var isIE11OrOlder = /Trident/.test(navigator.userAgent);
 
-// Patch document.importNode to work around IE11 bug that
-// casues children of a document fragment imported while
-// there is a mutation observer to not have a parentNode (!?!)
-if (isIE11OrOlder) {
-  (function() {
-    var importNode = document.importNode;
-    document.importNode = function() {
-      var n = importNode.apply(document, arguments);
-      // Copy all children to a new document fragment since
-      // this one may be broken
-      if (n.nodeType == n.DOCUMENT_FRAGMENT_NODE) {
-        var f = document.createDocumentFragment();
-        f.appendChild(n);
-        return f;
-      } else {
-        return n;
-      }
-    };
-  })();  
-}
-
 // If native, setup stub api and bail.
 // NOTE: we fire `WebComponentsReady` under native for api compatibility
 if (useNative) {
@@ -139,4 +118,7 @@ if (document.readyState === 'complete' || scope.flags.eager) {
   window.addEventListener(loadEvent, bootstrap);
 }
 
+// exports
+scope.isIE11OrOlder = isIE11OrOlder;
+
 })(window.CustomElements);
diff --git a/src/CustomElements/register.js b/src/CustomElements/register.js
index 45d9fc239..656920613 100644
--- a/src/CustomElements/register.js
+++ b/src/CustomElements/register.js
@@ -21,8 +21,9 @@
 CustomElements.addModule(function(scope) {
 
 // imports
+var isIE11OrOlder = scope.isIE11OrOlder;
 var upgradeDocumentTree = scope.upgradeDocumentTree;
-var upgrade = scope.upgrade;
+var upgradeAll = scope.upgradeAll;
 var upgradeWithDefinition = scope.upgradeWithDefinition;
 var implementPrototype = scope.implementPrototype;
 var useNative = scope.useNative;
@@ -291,20 +292,9 @@ function createElement(tag, typeExtension) {
   return element;
 }
 
-function cloneNode(deep) {
-  // call original clone
-  var n = domCloneNode.call(this, deep);
-  // upgrade the element and subtree
-  upgrade(n);
-  // return the clone
-  return n;
-}
-
 // capture native createElement before we override it
 var domCreateElement = document.createElement.bind(document);
 var domCreateElementNS = document.createElementNS.bind(document);
-// capture native cloneNode before we override it
-var domCloneNode = Node.prototype.cloneNode;
 
 // Create a custom 'instanceof'. This is necessary when CustomElements
 // are implemented via a mixin strategy, as for example on IE10.
@@ -329,11 +319,44 @@ if (!Object.__proto__ && !useNative) {
   };
 }
 
+// wrap a dom object method that works on nodes such that it forces upgrade 
+function wrapDomMethodToForceUpgrade(obj, methodName) {
+  var orig = obj[methodName];
+  obj[methodName] = function() {
+    var n = orig.apply(this, arguments);
+    upgradeAll(n);
+    return n;
+  };
+}
+
+wrapDomMethodToForceUpgrade(Node.prototype, 'cloneNode');
+wrapDomMethodToForceUpgrade(document, 'importNode');
+
+// Patch document.importNode to work around IE11 bug that
+// casues children of a document fragment imported while
+// there is a mutation observer to not have a parentNode (!?!)
+if (isIE11OrOlder) {
+  (function() {
+    var importNode = document.importNode;
+    document.importNode = function() {
+      var n = importNode.apply(document, arguments);
+      // Copy all children to a new document fragment since
+      // this one may be broken
+      if (n.nodeType == n.DOCUMENT_FRAGMENT_NODE) {
+        var f = document.createDocumentFragment();
+        f.appendChild(n);
+        return f;
+      } else {
+        return n;
+      }
+    };
+  })();  
+}
+
 // exports
 document.registerElement = register;
 document.createElement = createElement; // override
 document.createElementNS = createElementNS; // override
-Node.prototype.cloneNode = cloneNode; // override
 scope.registry = registry;
 scope.instanceof = isInstance;
 scope.reservedTagList = reservedTagList;
diff --git a/tests/CustomElements/js/customElements.js b/tests/CustomElements/js/customElements.js
index 48a06632b..398c9c553 100644
--- a/tests/CustomElements/js/customElements.js
+++ b/tests/CustomElements/js/customElements.js
@@ -364,6 +364,22 @@ suite('customElements', function() {
     done();
   });
 
+  test('document.importNode upgrades', function() {
+    var XImportPrototype = Object.create(HTMLElement.prototype);
+    XImportPrototype.createdCallback = function() {
+      this.__ready__ = true;
+    };
+    document.registerElement('x-import', {
+      prototype: XImportPrototype
+    });
+    var frag = document.createDocumentFragment();
+    frag.appendChild(document.createElement('x-import'));
+    assert.isTrue(frag.firstChild.__ready__, 'source element upgraded');
+    var imported = document.importNode(frag, true);
+    window.imported = imported;
+    assert.isTrue(imported.firstChild.__ready__, 'imported element upgraded');
+  });
+
   test('entered left apply to view', function() {
     var invocations = [];
     var elementProto = Object.create(HTMLElement.prototype);