only in patch2:
unchanged:
--- a/core/includes/entity.inc
+++ b/core/includes/entity.inc
@@ -267,7 +267,12 @@ function entity_revision_delete($entity_type, $revision_id) {
  */
 function entity_load_by_uuid($entity_type_id, $uuid, $reset = FALSE) {
   $entity_type = \Drupal::entityManager()->getDefinition($entity_type_id);
-  if (!$uuid_key = $entity_type->getKey('uuid')) {
+
+  // Configuration entities do not use annotations to set the UUID key.
+  if (is_subclass_of($entity_type->getClass(), 'Drupal\Core\Config\Entity\ConfigEntityBase')) {
+    $uuid_key = 'uuid';
+  }
+  elseif (!$uuid_key = $entity_type->getKey('uuid')) {
     throw new EntityStorageException("Entity type $entity_type_id does not support UUIDs.");
   }
 
only in patch2:
unchanged:
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigEntityUnitTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigEntityUnitTest.php
@@ -78,6 +78,13 @@ public function testStorageControllerMethods() {
     ));
     $entity->save();
 
+    // Ensure that the configuration entity can be loaded by UUID.
+    $entity_loaded_by_uuid = entity_load_by_uuid($entity_type->id(), $entity->uuid());
+    // Compare UUIDs as the objects are not identical since
+    // $entity->enforceIsNew is FALSE and $entity_loaded_by_uuid->enforceIsNew
+    // is NULL.
+    $this->assertIdentical($entity->uuid(), $entity_loaded_by_uuid->uuid());
+
     $entities = $this->storage->loadByProperties();
     $this->assertEqual(count($entities), 3, 'Three entities are loaded when no properties are specified.');