diff -u b/core/includes/common.inc b/core/includes/common.inc
--- b/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -268,8 +268,14 @@
 function drupal_get_profile() {
   global $install_state;
 
-  if (isset($install_state['parameters']['profile'])) {
-    $profile = $install_state['parameters']['profile'];
+  if (defined('MAINTENANCE_MODE') && (MAINTENANCE_MODE == 'install')) {
+    // If the profile has been selected return it.
+    if (isset($install_state['parameters']['profile'])) {
+      $profile = $install_state['parameters']['profile'];
+    }
+    else {
+      $profile = '';
+    }
   }
   else {
     $profile = Drupal::state()->get('profile.install') ?: 'standard';
only in patch2:
unchanged:
--- a/core/modules/system/lib/Drupal/system/Tests/Bootstrap/GetFilenameUnitTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Bootstrap/GetFilenameUnitTest.php
@@ -26,6 +26,11 @@ public static function getInfo() {
    * Tests that drupal_get_filename() works when the file is not in database.
    */
   function testDrupalGetFilename() {
+    // drupal_get_profile() is using obtaining the profile from state if the
+    // install_state global is not set.
+    global $install_state;
+    $install_state['parameters']['profile'] = 'testing';
+
     // Assert that the test is meaningful by making sure the keyvalue service
     // does not exist.
     $this->assertFalse(drupal_container()->has('keyvalue'), 'The container has no keyvalue service.');