diff --git a/platypush/backend/http/app/routes/plugins/camera/pi.py b/platypush/backend/http/app/routes/plugins/camera/pi.py
index 0e3c2234d..539ed1ef9 100644
--- a/platypush/backend/http/app/routes/plugins/camera/pi.py
+++ b/platypush/backend/http/app/routes/plugins/camera/pi.py
@@ -29,8 +29,9 @@ def video_feed():
                 frame = output.frame
 
             if frame and len(frame):
-                yield (b'--frame\r\n'
-                       b'Content-Type: image/jpeg\r\n\r\n' + frame + b'\r\n')
+                yield (
+                    b'--frame\r\n' b'Content-Type: image/jpeg\r\n\r\n' + frame + b'\r\n'
+                )
 
 
 @camera_pi.route('/camera/pi/frame', methods=['GET'])
@@ -38,18 +39,18 @@ def video_feed():
 def get_frame_img():
     filename = os.path.join(tempfile.gettempdir(), 'camera_pi.jpg')
     response = send_request('camera.pi.take_picture', image_file=filename)
-    frame_file = (response.output or {}).get('image_file')
+    frame_file = (response or {}).get('image_file')
     assert frame_file is not None
 
-    return send_from_directory(os.path.dirname(frame_file),
-                               os.path.basename(frame_file))
+    return send_from_directory(
+        os.path.dirname(frame_file), os.path.basename(frame_file)
+    )
 
 
 @camera_pi.route('/camera/pi/stream', methods=['GET'])
 @authenticate()
 def get_stream_feed():
-    return Response(video_feed(),
-                    mimetype='multipart/x-mixed-replace; boundary=frame')
+    return Response(video_feed(), mimetype='multipart/x-mixed-replace; boundary=frame')
 
 
 # vim:sw=4:ts=4:et:
diff --git a/platypush/backend/http/app/streaming/plugins/sound.py b/platypush/backend/http/app/streaming/plugins/sound.py
index 4101da841..14f94a49e 100644
--- a/platypush/backend/http/app/streaming/plugins/sound.py
+++ b/platypush/backend/http/app/streaming/plugins/sound.py
@@ -29,16 +29,12 @@ class SoundRoute(StreamingRoute):
 
     @contextmanager
     def _audio_stream(self, **kwargs) -> Generator[None, None, None]:
-        response = send_request(
+        send_request(
             'sound.record',
             dtype='int16',
             **kwargs,
         )
 
-        assert response and not response.is_error(), (
-            'Streaming error: ' + str(response.errors) if response else '(unknown)'
-        )
-
         yield
         send_request('sound.stop_recording')
 
diff --git a/platypush/backend/http/app/utils/bus.py b/platypush/backend/http/app/utils/bus.py
index 72f85658f..168e44fb8 100644
--- a/platypush/backend/http/app/utils/bus.py
+++ b/platypush/backend/http/app/utils/bus.py
@@ -64,4 +64,9 @@ def send_request(action, wait_for_response=True, **kwargs):
     if kwargs:
         msg['args'] = kwargs
 
-    return send_message(msg, wait_for_response=wait_for_response)
+    rs = send_message(msg, wait_for_response=wait_for_response)
+    assert rs, 'Got an empty response from the server'
+    if rs:
+        assert not rs.errors, '\n'.join(rs.errors)
+
+    return rs.output