diff --git a/src/entrypoints/authorize.ts b/src/entrypoints/authorize.ts
index 6150ebb7e0..36954a3fcf 100644
--- a/src/entrypoints/authorize.ts
+++ b/src/entrypoints/authorize.ts
@@ -4,6 +4,7 @@ import "../auth/ha-authorize";
 import "../resources/ha-style";
 import "../resources/roboto";
 import "../resources/safari-14-attachshadow-patch";
+import "../resources/array.flat.polyfill";
 
 /* polyfill for paper-dropdown */
 setTimeout(
diff --git a/src/entrypoints/onboarding.ts b/src/entrypoints/onboarding.ts
index 9c085ed82f..44a67890ab 100644
--- a/src/entrypoints/onboarding.ts
+++ b/src/entrypoints/onboarding.ts
@@ -4,6 +4,7 @@ import "../onboarding/ha-onboarding";
 import "../resources/ha-style";
 import "../resources/roboto";
 import "../resources/safari-14-attachshadow-patch";
+import "../resources/array.flat.polyfill";
 
 declare global {
   interface Window {