diff --git a/apps/mavlink/mavlink.c b/apps/mavlink/mavlink.c
index a94591424f..77034914ff 100644
--- a/apps/mavlink/mavlink.c
+++ b/apps/mavlink/mavlink.c
@@ -735,7 +735,7 @@ int mavlink_main(int argc, char *argv[])
 		mavlink_task = task_spawn("mavlink",
 					  SCHED_DEFAULT,
 					  SCHED_PRIORITY_DEFAULT,
-					  6000,
+					  2048,
 					  mavlink_thread_main,
 					  (const char**)argv);
 		exit(0);
diff --git a/apps/mavlink/mavlink_receiver.c b/apps/mavlink/mavlink_receiver.c
index 1801ddc9bf..fb59d07a17 100644
--- a/apps/mavlink/mavlink_receiver.c
+++ b/apps/mavlink/mavlink_receiver.c
@@ -202,6 +202,8 @@ handle_message(mavlink_message_t *msg)
 		mavlink_vicon_position_estimate_t pos;
 		mavlink_msg_vicon_position_estimate_decode(msg, &pos);
 
+		vicon_position.timestamp = hrt_absolute_time();
+
 		vicon_position.x = pos.x;
 		vicon_position.y = pos.y;
 		vicon_position.z = pos.z;
diff --git a/apps/mavlink/orb_listener.c b/apps/mavlink/orb_listener.c
index 254100b2e6..b0aa401fc2 100644
--- a/apps/mavlink/orb_listener.c
+++ b/apps/mavlink/orb_listener.c
@@ -754,8 +754,8 @@ uorb_receive_start(void)
 	pthread_attr_t uorb_attr;
 	pthread_attr_init(&uorb_attr);
 
-	/* Set stack size, needs more than 8000 bytes */
-	pthread_attr_setstacksize(&uorb_attr, 4096);
+	/* Set stack size, needs less than 2k */
+	pthread_attr_setstacksize(&uorb_attr, 2048);
 
 	pthread_t thread;
 	pthread_create(&thread, &uorb_attr, uorb_receive_thread, NULL);
diff --git a/apps/mavlink/orb_topics.h b/apps/mavlink/orb_topics.h
index 0eb2fabfd4..4650c49916 100644
--- a/apps/mavlink/orb_topics.h
+++ b/apps/mavlink/orb_topics.h
@@ -56,6 +56,7 @@
 #include <uORB/topics/optical_flow.h>
 #include <uORB/topics/actuator_outputs.h>
 #include <uORB/topics/actuator_controls_effective.h>
+#include <uORB/topics/actuator_controls.h>
 #include <uORB/topics/manual_control_setpoint.h>
 #include <uORB/topics/debug_key_value.h>
 #include <drivers/drv_rc_input.h>
diff --git a/apps/sensors/sensors.cpp b/apps/sensors/sensors.cpp
index fd71780cc1..71feb377b2 100644
--- a/apps/sensors/sensors.cpp
+++ b/apps/sensors/sensors.cpp
@@ -1188,7 +1188,7 @@ Sensors::start()
 	_sensors_task = task_spawn("sensors_task",
 				   SCHED_DEFAULT,
 				   SCHED_PRIORITY_MAX - 5,
-				   6000,	/* XXX may be excesssive */
+				   2048,
 				   (main_t)&Sensors::task_main_trampoline,
 				   nullptr);
 
diff --git a/apps/uORB/topics/actuator_controls_effective.h b/apps/uORB/topics/actuator_controls_effective.h
index 83f082c8a6..40278c56c2 100644
--- a/apps/uORB/topics/actuator_controls_effective.h
+++ b/apps/uORB/topics/actuator_controls_effective.h
@@ -55,7 +55,7 @@
 
 struct actuator_controls_effective_s {
 	uint64_t timestamp;
-	float	control_effective[NUM_ACTUATOR_CONTROLS];
+	float	control_effective[NUM_ACTUATOR_CONTROLS_EFFECTIVE];
 };
 
 /* actuator control sets; this list can be expanded as more controllers emerge */