diff --git a/src/html/index.html.template b/src/html/index.html.template
index efa0320b3c..3d9bf4461f 100644
--- a/src/html/index.html.template
+++ b/src/html/index.html.template
@@ -41,6 +41,7 @@
       }
     </style>
     <script>
+      window.customPanelJS = '<%= customPanelJS %>';
       window.noAuth = '{{ no_auth }}';
       window.useOAuth = '{{ use_oauth }}'
       window.Polymer = {
diff --git a/src/panels/custom/ha-panel-custom.js b/src/panels/custom/ha-panel-custom.js
index 3a21809918..412f576252 100644
--- a/src/panels/custom/ha-panel-custom.js
+++ b/src/panels/custom/ha-panel-custom.js
@@ -95,7 +95,7 @@ It will have access to all data in Home Assistant.
     `;
     const iframeDoc = this.querySelector('iframe').contentWindow.document;
     iframeDoc.open();
-    iframeDoc.write(`<script src='${__PUBLIC_PATH__}custom-panel.js'></script>`);
+    iframeDoc.write(`<script src='${window.customPanelJS}'></script>`);
     iframeDoc.close();
   }
 
diff --git a/webpack.config.js b/webpack.config.js
index 363a51df89..3b9b1b6d3f 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -190,6 +190,7 @@ function createConfig(isProdBuild, latestBuild) {
           compatibility: assets.chunks.compatibility.entry,
           appjs: assets.chunks.app.entry,
           corejs: assets.chunks.core.entry,
+          customPanelJS: assets.chunks['custom-panel'].entry,
         }),
         filename: `index.html`,
       }),