diff --git a/core/includes/path.inc b/core/includes/path.inc
index 0635f80..39a59ed 100644
--- a/core/includes/path.inc
+++ b/core/includes/path.inc
@@ -298,7 +298,13 @@ function drupal_is_front_page() {
   $is_front_page = &$drupal_static_fast['is_front_page'];
 
   if (!isset($is_front_page)) {
-    $is_front_page = (current_path() == config('system.site')->get('site_frontpage'));
+    // If we are in the install mode, then always return FALSE.
+    if (defined('MAINTENANCE_MODE') && MAINTENANCE_MODE == 'install') {
+      $is_front_page = FALSE;
+    }
+    else {
+      $is_front_page = (current_path() == config('system.site')->get('site_frontpage'));
+    }
   }
 
   return $is_front_page;
diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index 2223e43..f75b7d3 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -2712,18 +2712,26 @@ function template_preprocess_maintenance_page(&$variables) {
     $variables['layout'] = ($variables['layout'] == 'first') ? 'both' : 'second';
   }
 
-  $site_config = config('system.site');
+  $site_name = '';
+  $site_slogan = '';
+  // If we are not in the install mode, then load the site_name and site_slogan
+  // from config.
+  if (!(defined('MAINTENANCE_MODE') && MAINTENANCE_MODE == 'install')) {
+    $site_config = config('system.site');
+    $site_name = $site_config->get('site_name');
+    $site_slogan = $site_config->get('site_slogan');
+  }
   // Construct page title
   if (drupal_get_title()) {
     $head_title = array(
       'title' => strip_tags(drupal_get_title()),
-      'name' => $site_config->get('site_name'),
+      'name' => $site_name,
     );
   }
   else {
-    $head_title = array('name' => $site_config->get('site_name'));
-    if ($site_config->get('site_slogan')) {
-      $head_title['slogan'] = $site_config->get('site_slogan');
+    $head_title = array('name' => $site_name);
+    if ($site_slogan) {
+      $head_title['slogan'] = $site_slogan;
     }
   }
 
@@ -2740,8 +2748,8 @@ function template_preprocess_maintenance_page(&$variables) {
   $variables['messages']          = $variables['show_messages'] ? theme('status_messages') : '';
   $variables['main_menu']         = array();
   $variables['secondary_menu']    = array();
-  $variables['site_name']         = (theme_get_setting('toggle_name') ? $site_config->get('site_name') : '');
-  $variables['site_slogan']       = (theme_get_setting('toggle_slogan') ? $site_config->get('site_slogan') : '');
+  $variables['site_name']         = (theme_get_setting('toggle_name') ? $site_name : '');
+  $variables['site_slogan']       = (theme_get_setting('toggle_slogan') ? $site_slogan : '');
   $variables['tabs']              = '';
   $variables['title']             = drupal_get_title();
 
diff --git a/core/lib/Drupal/Core/Config/DatabaseStorage.php b/core/lib/Drupal/Core/Config/DatabaseStorage.php
index 42cfbcc..c736245 100644
--- a/core/lib/Drupal/Core/Config/DatabaseStorage.php
+++ b/core/lib/Drupal/Core/Config/DatabaseStorage.php
@@ -20,9 +20,6 @@ class DatabaseStorage extends StorageBase {
     // handle it if need be.
     $data = array();
     try {
-      if (!function_exists('db_query')) {
-        throw new Exception("no db_query");
-      }
       $raw = db_query('SELECT data FROM {config} WHERE name = :name', array(':name' => $this->name))->fetchField();
       if ($raw !== FALSE) {
         $data = $this->decode($raw);