diff --git a/android_app/app/src/main/java/com/health/openscale/gui/measurement/ChartMeasurementView.java b/android_app/app/src/main/java/com/health/openscale/gui/measurement/ChartMeasurementView.java
index d377d636..5ecd0e95 100644
--- a/android_app/app/src/main/java/com/health/openscale/gui/measurement/ChartMeasurementView.java
+++ b/android_app/app/src/main/java/com/health/openscale/gui/measurement/ChartMeasurementView.java
@@ -523,7 +523,7 @@ public class ChartMeasurementView extends LineChart {
             return;
         }
 
-        PolynomialFitter polyFitter = new PolynomialFitter(3);
+        PolynomialFitter polyFitter = new PolynomialFitter(lineEntries.size() == 2 ? 2 : 3);
 
         // use only the last 30 values for the polynomial fitter
         for (int i=1; i<30; i++) {
diff --git a/android_app/app/src/main/java/com/health/openscale/gui/preferences/BluetoothSettingsFragment.java b/android_app/app/src/main/java/com/health/openscale/gui/preferences/BluetoothSettingsFragment.java
index b73630ca..c77ec282 100644
--- a/android_app/app/src/main/java/com/health/openscale/gui/preferences/BluetoothSettingsFragment.java
+++ b/android_app/app/src/main/java/com/health/openscale/gui/preferences/BluetoothSettingsFragment.java
@@ -362,9 +362,13 @@ public class BluetoothSettingsFragment extends Fragment {
             Timber.d("Saved Bluetooth device " + device.getName() + " with address " + device.getAddress());
 
             stopBluetoothDiscovery();
-            Navigation.findNavController(requireActivity(), R.id.nav_host_fragment).getPreviousBackStackEntry().getSavedStateHandle().set("update", true);
-            Navigation.findNavController(requireActivity(), R.id.nav_host_fragment).navigateUp();
-        }
+
+            if (getActivity().findViewById(R.id.nav_host_fragment) != null){
+                Navigation.findNavController(requireActivity(), R.id.nav_host_fragment).getPreviousBackStackEntry().getSavedStateHandle().set("update", true);
+                Navigation.findNavController(requireActivity(), R.id.nav_host_fragment).navigateUp();
+            } else
+                getActivity().finish();
+            }
     }
 
     @Override