BoltExtensionOverrideRoutes.php

<?php

public function onMountControllerAfter(MountEvent $event){
    $app = $event->getApp();

    foreach ($this->registerFrontendControllers() as $prefix => $collection) {
        $event->mount($prefix, $collection);
    }

    if ($app['routes']->count() > 0) {
        $nullRoute = function(){ throw new NotFoundHttpException(); };
        $app['controllers']->match('/', $nullRoute)->bind('preview');
        $app['controllers']->match('/', $nullRoute)->bind('contentlink');
        $app['controllers']->match('/', $nullRoute)->bind('contentlisting');
        $app['controllers']->match('/', $nullRoute)->bind('taxonomylink');
    }
}


/** {@inheritdoc} */
public static function getSubscribedEvents() {
    return [
        ControllerEvents::MOUNT => [
            ['onMountControllerAfter' , -100],
        ],
    ];
}