diff --git a/build/module_args/v8.gni b/build/module_args/v8.gni
index e4bbf46..d42babd 100644
--- a/build/module_args/v8.gni
+++ b/build/module_args/v8.gni
@@ -6,5 +6,7 @@ if (is_android) {
   import("//build/config/android/config.gni")
 }
 
-v8_use_external_startup_data =
-    !((is_android && is_android_webview_build) || is_chromeos || is_win)
+# Many V8 users in mojo do not support external startup data for V8, so
+# we disable it. If enabled, special care should be taken to ensure the
+# appropriate startup data is correctly bundled for apps.
+v8_use_external_startup_data = false