core/modules/rest/rest.install                     | 10 ++++
 .../Update/EntityResourcePermissionsUpdateTest.php | 56 +++++++++++++++++++
 .../update/drupal-8.rest-rest_update_8201.php      | 63 ++++++++++++++++++++++
 3 files changed, 129 insertions(+)

diff --git a/core/modules/rest/rest.install b/core/modules/rest/rest.install
index 3b2f097..9a08e34 100644
--- a/core/modules/rest/rest.install
+++ b/core/modules/rest/rest.install
@@ -23,6 +23,12 @@ function rest_requirements($phase) {
 }
 
 /**
+ * @defgroup updates-8.1.x-to-8.2.x Updates from 8.1.x to 8.2.x
+ * @{
+ * Update functions from 8.1.x to 8.2.x.
+ */
+
+/**
  * Enable BC for EntityResource: continue to use permissions.
  */
 function rest_update_8201() {
@@ -31,3 +37,7 @@ function rest_update_8201() {
   $rest_settings->set('bc_entity_resource_permissions', TRUE)
     ->save(TRUE);
 }
+
+/**
+ * @} End of "defgroup updates-8.1.x-to-8.2.x".
+ */
diff --git a/core/modules/rest/src/Tests/Update/EntityResourcePermissionsUpdateTest.php b/core/modules/rest/src/Tests/Update/EntityResourcePermissionsUpdateTest.php
new file mode 100644
index 0000000..ff20c1e
--- /dev/null
+++ b/core/modules/rest/src/Tests/Update/EntityResourcePermissionsUpdateTest.php
@@ -0,0 +1,56 @@
+<?php
+
+namespace Drupal\rest\Tests\Update;
+
+use Drupal\system\Tests\Update\UpdatePathTestBase;
+
+/**
+ * Tests that existing sites continue to use permissions for EntityResource.
+ *
+ * @see https://www.drupal.org/node/2664780
+ *
+ * @group rest
+ */
+class EntityResourcePermissionsUpdateTest extends UpdatePathTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['rest', 'serialization'];
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setDatabaseDumpFiles() {
+    $this->databaseDumpFiles = [
+      __DIR__ . '/../../../../system/tests/fixtures/update/drupal-8.bare.standard.php.gz',
+      __DIR__ . '/../../../../rest/tests/fixtures/update/drupal-8.rest-rest_update_8201.php',
+    ];
+  }
+
+  /**
+   * Tests rest_update_8201().
+   */
+  public function testAllowedHtmlUpdate() {
+    $permission_handler = $this->container->get('user.permissions');
+
+    // Make sure we have the expected values before the update.
+    $rest_settings = $this->config('rest.settings');
+    $this->assertFalse(array_key_exists('bc_entity_resource_permissions', $rest_settings->getRawData()));
+    $this->assertFalse($permission_handler->moduleProvidesPermissions('rest'));
+
+    $this->runUpdates();
+
+    // Make sure we have the expected values after the update.
+    $rest_settings = $this->config('rest.settings');
+    $this->assertTrue(array_key_exists('bc_entity_resource_permissions', $rest_settings->getRawData()));
+    $this->assertTrue($rest_settings->get('bc_entity_resource_permissions'));
+    $this->assertTrue($permission_handler->moduleProvidesPermissions('rest'));
+    $permissions = $permission_handler->getPermissions();
+    $rest_permissions = array_keys(array_filter($permissions, function ($permission) {
+      return $permission['provider'] === 'rest';
+    }));
+    $this->assertEqual(['restful delete entity:node', 'restful get entity:node', 'restful patch entity:node', 'restful post entity:node'], $rest_permissions);
+  }
+
+}
diff --git a/core/modules/rest/tests/fixtures/update/drupal-8.rest-rest_update_8201.php b/core/modules/rest/tests/fixtures/update/drupal-8.rest-rest_update_8201.php
new file mode 100644
index 0000000..f035e94
--- /dev/null
+++ b/core/modules/rest/tests/fixtures/update/drupal-8.rest-rest_update_8201.php
@@ -0,0 +1,63 @@
+<?php
+
+/**
+ * @file
+ * Contains database additions to drupal-8.bare.standard.php.gz for testing the
+ * upgrade path of rest_update_8201().
+ */
+
+use Drupal\Core\Database\Database;
+
+$connection = Database::getConnection();
+
+// Set the schema version.
+$connection->insert('key_value')
+  ->fields([
+    'collection' => 'system.schema',
+    'name' => 'rest',
+    'value' => 'i:8000;',
+  ])
+  ->fields([
+    'collection' => 'system.schema',
+    'name' => 'serialization',
+    'value' => 'i:8000;',
+  ])
+  ->execute();
+
+// Update core.extension.
+$extensions = $connection->select('config')
+  ->fields('config', ['data'])
+  ->condition('collection', '')
+  ->condition('name', 'core.extension')
+  ->execute()
+  ->fetchField();
+$extensions = unserialize($extensions);
+$extensions['module']['rest'] = 8000;
+$extensions['module']['serialization'] = 8000;
+$connection->update('config')
+  ->fields([
+    'data' => serialize($extensions),
+  ])
+  ->condition('collection', '')
+  ->condition('name', 'core.extension')
+  ->execute();
+
+// Install the rest configuration.
+$config = [
+  'resources' => [
+    'entity:node' => [
+      'GET' => [
+        'supported_formats' => ['json'],
+        'supported_auth' => [],
+      ],
+    ],
+  ],
+  'link_domain' => '~',
+];
+$data = $connection->insert('config')
+  ->fields([
+    'name' => 'rest.settings',
+    'data' => serialize($config),
+    'collection' => ''
+  ])
+  ->execute();