diff --git a/sw/airborne/fms/fms_autopilot_msg.h b/sw/airborne/fms/fms_autopilot_msg.h
index 79bacecc4a..7c90141c81 100644
--- a/sw/airborne/fms/fms_autopilot_msg.h
+++ b/sw/airborne/fms/fms_autopilot_msg.h
@@ -55,6 +55,16 @@ struct __attribute__ ((packed)) AutopilotMessageTWDown
 /*
  * Passthrough, aka biplan
  */
+
+/* used to indicate parts of the message which actually represent a new measurement */
+struct PTUpValidFlags
+{
+  unsigned rc:1;
+  unsigned pressure:1;
+  unsigned vane:1;
+  unsigned imu:1;
+};
+
 struct __attribute__ ((packed)) AutopilotMessagePTUp
 {
   struct Int32Rates gyro;
@@ -70,6 +80,7 @@ struct __attribute__ ((packed)) AutopilotMessagePTUp
   int16_t rc_aux3;
   int16_t rc_aux4;
   uint8_t rc_status;
+  struct PTUpValidFlags valid;
 };
 
 struct __attribute__ ((packed)) AutopilotMessagePTDown
diff --git a/sw/airborne/fms/fms_spi_autopilot_msg.c b/sw/airborne/fms/fms_spi_autopilot_msg.c
index 71a31c14ef..3f2fb62382 100644
--- a/sw/airborne/fms/fms_spi_autopilot_msg.c
+++ b/sw/airborne/fms/fms_spi_autopilot_msg.c
@@ -97,11 +97,12 @@ int spi_ap_link_init()
 
 static void passthrough_up_parse(struct AutopilotMessagePTUp *msg_up)
 {
-  // FIXME: Should only callback when there is something new
-  // FIXME: placeholders since the vane and pressure data fields don't exist yet
-  if (vane_callback)
+
+  if (msg_up->valid.vane && vane_callback)
+    // FIXME: placeholders since the vane and pressure data fields don't exist yet
     vane_callback(0, 0., 0.);
-  if (pressure_callback)
+
+  if (msg_up->valid.pressure && pressure_callback)
     pressure_callback(0, 0, 0);
 
   // Fill radio data
@@ -116,7 +117,7 @@ static void passthrough_up_parse(struct AutopilotMessagePTUp *msg_up)
   radio_control.values[RADIO_CONTROL_AUX4] = msg_up->rc_aux4;
   radio_control.status = msg_up->rc_status;
   
-  if (radio_control_callback)
+  if (msg_up->valid.rc && radio_control_callback)
     radio_control_callback();
 
   // Fill IMU data
@@ -132,7 +133,8 @@ static void passthrough_up_parse(struct AutopilotMessagePTUp *msg_up)
   imu.mag.y = MAG_FLOAT_OF_BFP(msg_up->mag.y);
   imu.mag.z = MAG_FLOAT_OF_BFP(msg_up->mag.z);
 
-  rdyb_booz_imu_update(&imu);
+  if (msg_up->valid.imu)
+    rdyb_booz_imu_update(&imu);
 }
 
 static void passthrough_down_fill(struct AutopilotMessagePTDown *msg_out)
@@ -144,8 +146,8 @@ static void passthrough_down_fill(struct AutopilotMessagePTDown *msg_out)
 
 void spi_ap_link_periodic()
 {
-  struct AutopilotMessagePTUp msg_in;
-  struct AutopilotMessagePTDown msg_out;
+  static struct AutopilotMessagePTUp msg_in;
+  static struct AutopilotMessagePTDown msg_out;
 
   passthrough_down_fill(&msg_out);
 
diff --git a/sw/airborne/lisa/lisa_stm_passthrough_main.c b/sw/airborne/lisa/lisa_stm_passthrough_main.c
index ad46828a55..64728f55d3 100644
--- a/sw/airborne/lisa/lisa_stm_passthrough_main.c
+++ b/sw/airborne/lisa/lisa_stm_passthrough_main.c
@@ -41,6 +41,8 @@ static inline void on_mag_event(void);
 static inline void main_on_overo_msg_received(void);
 static inline void main_on_overo_link_lost(void);
 
+static bool_t new_radio_msg;
+
 int main(void) {
 
 	main_init();
@@ -54,6 +56,10 @@ int main(void) {
 	return 0;
 }
 
+static void on_rc_message(void) {
+  new_radio_msg = TRUE;
+}
+
 static inline void main_init(void) {
 
 	hw_init();
@@ -75,10 +81,17 @@ static inline void main_event(void) {
 
 	BoozImuEvent(on_gyro_accel_event, on_mag_event);
 	OveroLinkEvent(main_on_overo_msg_received);
-	RadioControlEvent(NULL);
+	RadioControlEvent(on_rc_message);
 }
 
 static inline void main_on_overo_msg_received(void) {
+
+	if (new_radio_msg) overo_link.up.msg.valid.rc = 1;
+	else overo_link.up.msg.valid.rc = 0;
+        new_radio_msg = FALSE;
+
+	overo_link.up.msg.valid.imu = 1;
+
 	RATES_COPY(overo_link.up.msg.gyro, booz_imu.gyro);
 
 	VECT3_COPY(overo_link.up.msg.accel, booz_imu.accel);