diff --git a/lib/build/index.js b/lib/build/index.js
index 4e7a8f15dc..4afca04448 100644
--- a/lib/build/index.js
+++ b/lib/build/index.js
@@ -276,7 +276,7 @@ function getWebpackServerConfig () {
 function createWebpackMiddlewares () {
   const clientConfig = getWebpackClientConfig.call(this)
   // setup on the fly compilation + hot-reload
-  clientConfig.entry.app = ['webpack-hot-middleware/client?reload=true', clientConfig.entry.app]
+  clientConfig.entry.app = _.flatten(['webpack-hot-middleware/client?reload=true', clientConfig.entry.app])
   clientConfig.plugins.push(
     new webpack.HotModuleReplacementPlugin(),
     new webpack.NoErrorsPlugin()