diff --git a/react-packager/src/DependencyResolver/haste/DependencyGraph/__tests__/DependencyGraph-test.js b/react-packager/src/DependencyResolver/haste/DependencyGraph/__tests__/DependencyGraph-test.js
index bbdb0641..8ebe9c5a 100644
--- a/react-packager/src/DependencyResolver/haste/DependencyGraph/__tests__/DependencyGraph-test.js
+++ b/react-packager/src/DependencyResolver/haste/DependencyGraph/__tests__/DependencyGraph-test.js
@@ -166,6 +166,69 @@ describe('DependencyGraph', function() {
       });
     });
 
+    pit('should default main package to index.js', function() {
+      var root = '/root';
+      fs.__setMockFilesystem({
+        'root': {
+          'index.js': 'require("aPackage")',
+          'aPackage': {
+            'package.json': JSON.stringify({
+              name: 'aPackage',
+            }),
+            'index.js': 'lol',
+          }
+        }
+      });
+
+      var dgraph = new DependencyGraph({
+        roots: [root],
+        fileWatcher: fileWatcher
+      });
+      return dgraph.load().then(function() {
+        expect(dgraph.getOrderedDependencies('/root/index.js'))
+          .toEqual([
+            {id: '/root/index.js', path: '/root/index.js', dependencies: ['aPackage']},
+            { id: 'aPackage/index',
+              path: '/root/aPackage/index.js',
+              dependencies: []
+            },
+          ]);
+      });
+    });
+
+    pit('should default use index.js if main is a dir', function() {
+      var root = '/root';
+      fs.__setMockFilesystem({
+        'root': {
+          'index.js': 'require("aPackage")',
+          'aPackage': {
+            'package.json': JSON.stringify({
+              name: 'aPackage',
+              main: 'lib',
+            }),
+            lib: {
+              'index.js': 'lol',
+            },
+          }
+        }
+      });
+
+      var dgraph = new DependencyGraph({
+        roots: [root],
+        fileWatcher: fileWatcher
+      });
+      return dgraph.load().then(function() {
+        expect(dgraph.getOrderedDependencies('/root/index.js'))
+          .toEqual([
+            {id: '/root/index.js', path: '/root/index.js', dependencies: ['aPackage']},
+            { id: 'aPackage/lib/index',
+              path: '/root/aPackage/lib/index.js',
+              dependencies: []
+            },
+          ]);
+      });
+    });
+
     pit('should ignore malformed packages', function() {
       var root = '/root';
       fs.__setMockFilesystem({
diff --git a/react-packager/src/DependencyResolver/haste/DependencyGraph/index.js b/react-packager/src/DependencyResolver/haste/DependencyGraph/index.js
index 14139159..4622864d 100644
--- a/react-packager/src/DependencyResolver/haste/DependencyGraph/index.js
+++ b/react-packager/src/DependencyResolver/haste/DependencyGraph/index.js
@@ -184,6 +184,12 @@ DependecyGraph.prototype.resolveDependency = function(
     var main = packageJson.main || 'index';
     modulePath = withExtJs(path.join(packageJson._root, main));
     dep = this._graph[modulePath];
+
+    // Some packages use just a dir and rely on an index.js inside that dir.
+    if (dep == null) {
+      dep = this._graph[path.join(packageJson._root, main, 'index.js')];
+    }
+
     if (dep == null) {
       throw new Error(
         'Cannot find package main file for package: ' + packageJson._root
diff --git a/react-packager/src/DependencyResolver/haste/polyfills/require.js b/react-packager/src/DependencyResolver/haste/polyfills/require.js
index e7fdde25..00955ba4 100644
--- a/react-packager/src/DependencyResolver/haste/polyfills/require.js
+++ b/react-packager/src/DependencyResolver/haste/polyfills/require.js
@@ -196,7 +196,7 @@
     if (!module) {
       msg = 'Requiring unknown module "' + id + '"';
       if (__DEV__) {
-        msg += '. It may not be loaded yet. Did you forget to run arc build?';
+        msg += '. If you are sure the module is there, try restarting the packager.';
       }
       throw new ModuleError(msg);
     }
diff --git a/react-packager/src/Server/__tests__/Server-test.js b/react-packager/src/Server/__tests__/Server-test.js
index 8e638311..aa7ca349 100644
--- a/react-packager/src/Server/__tests__/Server-test.js
+++ b/react-packager/src/Server/__tests__/Server-test.js
@@ -186,6 +186,7 @@ describe('processRequest', function() {
           expect(packageFunc.mock.calls.length).toBe(1);
           triggerFileChange('all','path/file.js', options.projectRoots[0]);
           jest.runAllTimers();
+          jest.runAllTimers();
         })
         .then(function() {
           expect(packageFunc.mock.calls.length).toBe(2);
diff --git a/react-packager/src/Server/index.js b/react-packager/src/Server/index.js
index cc4f0bdf..19ec0039 100644
--- a/react-packager/src/Server/index.js
+++ b/react-packager/src/Server/index.js
@@ -92,8 +92,10 @@ Server.prototype._rebuildPackages = function() {
   Object.keys(packages).forEach(function(key) {
     var options = getOptionsFromUrl(key);
     // Wait for a previous build (if exists) to finish.
-    packages[key] = (packages[key] || q()).then(function() {
-      return buildPackage(options).then(function(p) {
+    packages[key] = (packages[key] || q()).finally(function() {
+      // With finally promise callback we can't change the state of the promise
+      // so we need to reassign the promise.
+      packages[key] = buildPackage(options).then(function(p) {
         // Make a throwaway call to getSource to cache the source string.
         p.getSource({
           inlineSourceMap: options.dev,
@@ -102,6 +104,7 @@ Server.prototype._rebuildPackages = function() {
         return p;
       });
     });
+    return packages[key];
   });
 };