diff --git a/core/modules/system/src/Controller/DbUpdateController.php b/core/modules/system/src/Controller/DbUpdateController.php
index 28ab72b..e66a1a5 100644
--- a/core/modules/system/src/Controller/DbUpdateController.php
+++ b/core/modules/system/src/Controller/DbUpdateController.php
@@ -228,7 +228,8 @@ protected function info(Request $request) {
       '#type' => 'link',
       '#title' => $this->t('Continue'),
       '#attributes' => array('class' => array('button', 'button--primary')),
-      '#url' => Url::fromUri($request->getUriForPath('/selection')),
+      // @todo Revisit once https://www.drupal.org/node/2548095 is in.
+      '#url' => Url::fromUri('base://selection'),
     );
     return $build;
   }
@@ -484,6 +485,9 @@ protected function results(Request $request) {
    */
   public function requirements($severity, array $requirements, Request $request) {
     $options = $severity == REQUIREMENT_WARNING ? array('continue' => 1) : array();
+    // @todo Revisit once https://www.drupal.org/node/2548095 is in. Something
+    // like Url::fromRoute('system.db_update')->setOptions ... should then be
+    // possible.
     $try_again_url = Url::fromUri($request->getUriForPath(''))->setOptions(['query' => $options])->toString(TRUE)->getGeneratedUrl();
 
     $build['status_report'] = array(
@@ -580,7 +584,8 @@ protected function triggerBatch(Request $request) {
     );
     batch_set($batch);
 
-    return batch_process(Url::fromUri($request->getUriForPath('/results')), Url::fromUri($request->getUriForPath('/start')));
+    // @todo Revisit once https://www.drupal.org/node/2548095 is in.
+    return batch_process(Url::fromUri('base://results'), Url::fromUri('base://start'));
   }
 
   /**
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 865e101..e07fa56 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -249,7 +249,7 @@ function system_theme_suggestions_html(array $variables) {
     $path_args = [''];
   }
   else {
-    $path_args = explode('/', Url::fromRoute('<current>')->getInternalPath());
+    $path_args = explode('/', ltrim(\Drupal::service('path.current')->getPath(), '/'));
   }
   return theme_get_suggestions($path_args, 'html');
 }