diff --git a/core/lib/Drupal/Core/Extension/ModuleInstaller.php b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
index c9308fb..d9d39c8 100644
--- a/core/lib/Drupal/Core/Extension/ModuleInstaller.php
+++ b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
@@ -97,7 +97,7 @@ public function install(array $module_list, $enable_dependencies = TRUE) {
     }
 
     // Required for module installation checks.
-    include_once DRUPAL_ROOT . '/core/includes/install.inc';
+    include_once $this->root . '/core/includes/install.inc';
 
     /** @var \Drupal\Core\Config\ConfigInstaller $config_installer */
     $config_installer = \Drupal::service('config.installer');
@@ -144,7 +144,7 @@ public function install(array $module_list, $enable_dependencies = TRUE) {
             $module_path = drupal_get_path('module', $name);
             $pathname = "$module_path/$name.info.yml";
             $filename = file_exists($module_path . "/$name.module") ? "$name.module" : NULL;
-            $module_filenames[$name] = new Extension('module', $pathname, $filename);
+            $module_filenames[$name] = new Extension($this->root, 'module', $pathname, $filename);
           }
         }
 
@@ -308,12 +308,13 @@ public function uninstall(array $module_list, $uninstall_dependents = TRUE) {
     // configured as enabled. Custom or overridden module handlers might contain
     // the module already, which means that it might be loaded, but not
     // necessarily installed.
+    $schema_store = \Drupal::keyValue('system.schema');
+    $entity_manager = \Drupal::entityManager();
     foreach ($module_list as $module) {
 
       // Clean up all entity bundles (including fields) of every entity type
       // provided by the module that is being uninstalled.
       // @todo Clean this up in https://www.drupal.org/node/2350111.
-      $entity_manager = \Drupal::entityManager();
       foreach ($entity_manager->getDefinitions() as $entity_type_id => $entity_type) {
         if ($entity_type->getProvider() == $module) {
           foreach (array_keys($entity_manager->getBundleInfo($entity_type_id)) as $bundle) {
@@ -346,7 +347,6 @@ public function uninstall(array $module_list, $uninstall_dependents = TRUE) {
       drupal_uninstall_schema($module);
 
       // Remove the module's entry from the config.
-      $extension_config = \Drupal::config('core.extension');
       $extension_config->clear("module.$module")->save();
 
       // Update the module handler to remove the module.
@@ -382,7 +382,6 @@ public function uninstall(array $module_list, $uninstall_dependents = TRUE) {
 
       \Drupal::logger('system')->info('%module module uninstalled.', array('%module' => $module));
 
-      $schema_store = \Drupal::keyValue('system.schema');
       $schema_store->delete($module);
     }
     drupal_get_installed_schema_version(NULL, TRUE);