It works!

app/base/routing.js

@@ -9,5 +9,19 @@ export default class BaseRoute extends Route {
   async beforeModel(transition) {
     this.session.requireAuthentication(transition, 'login');
     await this.currentUser.loadCurrentUser();
+    if (this.currentUser.user) {
+      await this.currentUser.user.home_folder;
+    }
+  }
+
+  setupController(controller, model) {
+    super.setupController(...arguments);
+
+    let app_controller = this.controllerFor('authenticated');
+
+    this.currentUser.user.home_folder.then((home_folder) => {
+      app_controller.set('home_folder', home_folder);
+    });
+
   }
 }

app/routes/application.js

@@ -11,4 +11,8 @@ export default class ApplicationRoute extends BaseRoute {
       return this.currentUser.user.home_folder;
     }
   }
+
+  setupController(controller, model) {
+    controller.set('home_folder', model);
+  }
 }

app/routes/authenticated/index.js

@@ -19,4 +19,5 @@ export default class IndexRoute extends Route {
       that.replaceWith("authenticated.nodes", home_folder.id);
     });
   }
+
 }

app/routes/authenticated/nodes.js

@@ -34,7 +34,8 @@ export default class FolderRoute extends Route {
   }
 
   setupController(controller, model) {
-    let _controller = this.controllerFor('authenticated.nodes');
+    let _controller = this.controllerFor('authenticated.nodes'),
+      _auth_controller = this.controllerFor('authenticated');
 
     if (model.extranode) {
       _controller.set('dualpanel_mode', true);
@@ -45,6 +46,6 @@ export default class FolderRoute extends Route {
     }
 
     _controller.set('mainnode', model.node);
-    _controller.set('home_folder', model.home_folder);
+    _auth_controller.set('home_folder', model.home_folder);
   }
 }

app/routes/authenticated/roles/index.js

-import Route from '@ember/routing/route';
+import BaseRoute from 'papermerge/base/routing';
 import { inject as service } from '@ember/service';
 
-export default class RolesRoute extends Route {
-  @service store;
-  @service session;
 
-  beforeModel(transition) {
-    this.session.requireAuthentication(transition, 'login');
-  }
+export default class RolesRoute extends BaseRoute {
+  @service store;
 
   async model() {
     return this.store.findAll('role');

app/templates/authenticated.hbs

 <main>
-  <Nav::Sidebar @home_folder={{@model}} />
+  <Nav::Sidebar @home_folder={{this.home_folder}} />
   <div class="w-100 central-bar">
     <Nav::Topbar />
     <div class="container-fluid mx-2 my-1">