diff --git a/src/main/java/ru/touchin/roboswag/components/navigation/FragmentNavigation.java b/src/main/java/ru/touchin/roboswag/components/navigation/FragmentNavigation.java
index 0b1de69..0cb8c7d 100644
--- a/src/main/java/ru/touchin/roboswag/components/navigation/FragmentNavigation.java
+++ b/src/main/java/ru/touchin/roboswag/components/navigation/FragmentNavigation.java
@@ -135,7 +135,8 @@ public class FragmentNavigation {
 
     @SuppressWarnings("PMD.ShortMethodName")
     public boolean up() {
-        return backTo(backStackEntry -> backStackEntry.getName().endsWith(TOP_FRAGMENT_TAG_MARK));
+        return backTo(backStackEntry ->
+                backStackEntry.getName() != null && backStackEntry.getName().endsWith(TOP_FRAGMENT_TAG_MARK));
     }
 
     public void push(@NonNull final Class<? extends Fragment> fragmentClass) {
diff --git a/src/main/java/ru/touchin/roboswag/components/navigation/ViewController.java b/src/main/java/ru/touchin/roboswag/components/navigation/ViewController.java
index f688f47..500918e 100644
--- a/src/main/java/ru/touchin/roboswag/components/navigation/ViewController.java
+++ b/src/main/java/ru/touchin/roboswag/components/navigation/ViewController.java
@@ -123,6 +123,12 @@ public class ViewController<TLogic extends Logic,
                 .takeUntil(isDestroyedSubject.filter(isDestroyed -> isDestroyed));
     }
 
+    @NonNull
+    protected <T> Observable<T> untilStop(@NonNull final Observable<T> observable) {
+        return observable.observeOn(AndroidSchedulers.mainThread())
+                .takeUntil(isStartedSubject.filter(isStarted -> !isStarted));
+    }
+
     public void onStart() {
         isStartedSubject.onNext(true);
     }