diff --git a/apps/theming/appinfo/routes.php b/apps/theming/appinfo/routes.php
index a6511668d1..a8436ab254 100644
--- a/apps/theming/appinfo/routes.php
+++ b/apps/theming/appinfo/routes.php
@@ -76,7 +76,6 @@ return ['routes' => [
 		'name'	=> 'Icon#getThemedIcon',
 		'url' => '/img/{app}/{image}',
 		'verb' => 'GET',
-		'defaults' => array("app" => "core"),
 		'requirements' => array('image' => '.+')
 	],
 ]];
diff --git a/apps/theming/lib/Controller/IconController.php b/apps/theming/lib/Controller/IconController.php
index 7ceaa59923..6e51f10c4c 100644
--- a/apps/theming/lib/Controller/IconController.php
+++ b/apps/theming/lib/Controller/IconController.php
@@ -109,7 +109,7 @@ class IconController extends Controller {
 	 * @param $app app name
 	 * @return StreamResponse|DataResponse
 	 */
-	public function getFavicon($app) {
+	public function getFavicon($app="core") {
 		// TODO: we need caching here
 		$icon = $this->renderAppIcon($app);
 		$icon->resizeImage(32, 32, Imagick::FILTER_LANCZOS, 1);
@@ -130,7 +130,7 @@ class IconController extends Controller {
 	 * @param $app app name
 	 * @return StreamResponse|DataResponse
 	 */
-	public function getTouchIcon($app) {
+	public function getTouchIcon($app="core") {
 		// TODO: we need caching here
 		$icon = $this->renderAppIcon($app);
 		$icon->resizeImage(512, 512, Imagick::FILTER_LANCZOS, 1);
diff --git a/lib/private/URLGenerator.php b/lib/private/URLGenerator.php
index 8972f1602e..f8b79dedd8 100644
--- a/lib/private/URLGenerator.php
+++ b/lib/private/URLGenerator.php
@@ -158,8 +158,10 @@ class URLGenerator implements IURLGenerator {
 		// Check if the app is in the app folder
 		$path = '';
 		if(\OCP\App::isEnabled('theming') && $image === "favicon.ico") {
+			if($app==="") { $app = "core"; }
 			$path = $this->linkToRoute('theming.Icon.getFavicon', [ 'app' => $app ]);
 		} elseif(\OCP\App::isEnabled('theming') && $image === "favicon-touch.png") {
+			if($app==="") { $app = "core"; }
 			$path = $this->linkToRoute('theming.Icon.getTouchIcon', [ 'app' => $app ]);
 		} elseif (file_exists(\OC::$SERVERROOT . "/themes/$theme/apps/$app/img/$image")) {
 			$path = \OC::$WEBROOT . "/themes/$theme/apps/$app/img/$image";