diff -u b/core/lib/Drupal/Core/Extension/UpdateModuleHandler.php b/core/lib/Drupal/Core/Extension/UpdateModuleHandler.php
--- b/core/lib/Drupal/Core/Extension/UpdateModuleHandler.php
+++ b/core/lib/Drupal/Core/Extension/UpdateModuleHandler.php
@@ -25,19 +25,28 @@
       return array();
     }
     switch ($hook) {
+      // hook_requirements is necessary for updates to work.
       case 'requirements':
+      // Allow logging.
       case 'watchdog':
         return parent::getImplementations($hook);
+      // Forms and pages do not render without the basic elements defined in
+      // system_element_info().
       case 'element_info':
-      case 'stream_wrappers':
+      // Forms do not render without the basic elements in
+      // drupal_common_theme() called from system_theme().
       case 'theme':
+      // user_update_8011() uses public:// to create the image style directory.
+      case 'stream_wrappers':
         return array('system');
+      // This is called during rebuild to find testing themes.
       case 'system_theme_info':
+      // @todo: remove this.
       case 'entity_info':
         return array();
+      // t() in system_stream_wrappers() needs this. Other schema calls aren't
+      // supported.
       case 'schema':
-        // t() in system_stream_wrappers() needs this. Other schema calls
-        // aren't supported.
         return array('locale');
       default:
         throw new \LogicException("Invoking hooks $hook is not supported during updates");