diff --git a/packages/ember-cli-fastboot/addon/initializers/render-mode.js b/packages/ember-cli-fastboot/addon/initializers/render-mode.js
index 39f76794..3779f2bd 100644
--- a/packages/ember-cli-fastboot/addon/initializers/render-mode.js
+++ b/packages/ember-cli-fastboot/addon/initializers/render-mode.js
@@ -11,7 +11,7 @@ export function initialize() {
       ApplicationInstance.prototype._bootSync = function (options) {
         this._bootSyncOld({
           ...options,
-          _rendermode: 'rehydrate',
+          _renderMode: 'rehydrate',
         });
       };