diff --git a/build_support/mini_require.js b/build_support/mini_require.js
index ee0d22d6c07..489711629ac 100644
--- a/build_support/mini_require.js
+++ b/build_support/mini_require.js
@@ -61,10 +61,13 @@ var _define = function(module, deps, payload) {
     if (arguments.length == 2)
         payload = deps;
 
-    if (!_define.modules)
-        _define.modules = {};
-
-    _define.modules[module] = payload;
+    if (!_define.modules) {
+        _define.modules = Object.create(null);
+        _define.payloads = Object.create(null);
+    }
+    
+    _define.payloads[module] = payload;
+    define.modules[module] = null;
 };
 
 /**
@@ -130,30 +133,27 @@ var lookup = function(parentId, moduleName) {
 
     var module = _define.modules[moduleName];
     if (!module) {
-        return null;
-    }
-
-    if (typeof module === 'function') {
-        var exports = {};
-        var mod = {
-            id: moduleName,
-            uri: '',
-            exports: exports,
-            packaged: true
-        };
-
-        var req = function(module, callback) {
-            return _require(moduleName, module, callback);
-        };
-
-        var returnValue = module(req, exports, mod);
-        exports = returnValue || mod.exports;
-
-        // cache the resulting module object for next time
-        _define.modules[moduleName] = exports;
-        return exports;
+        module = _define.payloads[moduleName];
+        if (typeof module === 'function') {
+            var exports = {};
+            var mod = {
+                id: moduleName,
+                uri: '',
+                exports: exports,
+                packaged: true
+            };
+
+            var req = function(module, callback) {
+                return _require(moduleName, module, callback);
+            };
+
+            var returnValue = module(req, exports, mod);
+            exports = returnValue || mod.exports;
+            _define.modules[moduleName] = exports;
+            delete _define.payloads[moduleName];
+        }
+        module = _define.modules[moduleName] = exports;
     }
-
     return module;
 };