diff --git a/core/modules/file/file.install b/core/modules/file/file.install
index 2cd6e12..1b9ee60 100644
--- a/core/modules/file/file.install
+++ b/core/modules/file/file.install
@@ -263,14 +263,15 @@ function file_update_8001() {
 
       foreach ($field['bundles'] as $etype => $bundles) {
         foreach ($bundles as $bundle) {
-          $instance = field_info_instance($etype, $field['field_name'], $bundle);
-          if (!empty($instance->definition['settings']['default_image'])) {
-            $instance->definition['settings']['default_image'] = array($instance->definition['settings']['default_image']);
+          if ($instance = field_read_instance($etype, $field['field_name'], $bundle)) {
+            if (!empty($instance['settings']['default_image'])) {
+              $instance['settings']['default_image'] = array($instance['settings']['default_image']);
+            }
+            else {
+              $instance['settings']['default_image'] = array();
+            }
+            field_update_instance($instance);
           }
-          else {
-            $instance->definition['settings']['default_image'] = array();
-          }
-          field_update_instance($instance->definition);
         }
       }
     }
diff --git a/core/modules/system/lib/Drupal/system/Tests/Upgrade/UserPictureUpgradePathTest.php b/core/modules/system/lib/Drupal/system/Tests/Upgrade/UserPictureUpgradePathTest.php
index 04070c9..c26dd86 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Upgrade/UserPictureUpgradePathTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Upgrade/UserPictureUpgradePathTest.php
@@ -40,8 +40,8 @@ public function testUserPictureUpgrade() {
 
     // Retrieve the field instance and check for migrated settings.
     $instance = field_info_instance('user', 'user_picture', 'user');
-    $file = entity_load('file', $instance['settings']['default_image']);
-    $this->assertIdentical($instance['settings']['default_image'], $file->id(), 'Default user picture has been migrated.');
+    $file = entity_load('file', $instance['settings']['default_image'][0]);
+    $this->assertIdentical($instance['settings']['default_image'][0], $file->id(), 'Default user picture has been migrated.');
     $this->assertEqual($file->uri, 'public://user_pictures_dir/druplicon.png', 'File id matches the uri expected.');
     $this->assertEqual($file->filename, 'druplicon.png');
     $this->assertEqual($file->langcode, LANGUAGE_NOT_SPECIFIED);