diff --git a/.gitmodules b/.gitmodules
index 6a4f815d42..b05de95995 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -4,9 +4,9 @@
 [submodule "NuttX"]
 	path = NuttX
 	url = git://github.com/PX4/NuttX.git
-[submodule "uavcan"]
+[submodule "libuavcan"]
 	path = src/lib/uavcan
-	url = git://github.com/pavel-kirienko/uavcan.git
+	url = git://github.com/UAVCAN/libuavcan.git
 [submodule "Tools/genmsg"]
 	path = Tools/genmsg
 	url = https://github.com/ros/genmsg.git
diff --git a/Makefile b/Makefile
index 47fe326b92..aedf595aef 100644
--- a/Makefile
+++ b/Makefile
@@ -51,10 +51,6 @@ endif
 
 GIT_DESC_SHORT := $(shell echo $(GIT_DESC) | cut -c1-16)
 
-$(shell echo "#include <systemlib/git_version.h>" > $(BUILD_DIR)git_version.c)
-$(shell echo "const char* px4_git_version = \"$(GIT_DESC)\";" >> $(BUILD_DIR)git_version.c)
-$(shell echo "const uint64_t px4_git_version_binary = 0x$(GIT_DESC_SHORT);" >> $(BUILD_DIR)git_version.c)
-
 #
 # Canned firmware configurations that we (know how to) build.
 #
@@ -129,7 +125,7 @@ $(STAGED_FIRMWARES): $(IMAGE_DIR)%.px4: $(BUILD_DIR)%.build/firmware.px4
 .PHONY: $(FIRMWARES)
 $(BUILD_DIR)%.build/firmware.px4: config   = $(patsubst $(BUILD_DIR)%.build/firmware.px4,%,$@)
 $(BUILD_DIR)%.build/firmware.px4: work_dir = $(BUILD_DIR)$(config).build/
-$(FIRMWARES): $(BUILD_DIR)%.build/firmware.px4:	generateuorbtopicheaders checksubmodules
+$(FIRMWARES): $(BUILD_DIR)%.build/firmware.px4:	checkgitversion generateuorbtopicheaders checksubmodules
 	@$(ECHO) %%%%
 	@$(ECHO) %%%% Building $(config) in $(work_dir)
 	@$(ECHO) %%%%
@@ -216,11 +212,53 @@ menuconfig:
 	@$(ECHO) ""
 endif
 
-$(NUTTX_SRC): checksubmodules
+$(NUTTX_SRC): checkgitversion checksubmodules
 
 $(UAVCAN_DIR):
 	$(Q) (./Tools/check_submodules.sh)
 
+
+ifeq ($(PX4_TARGET_OS),nuttx)
+# TODO
+# Move the above nuttx specific rules into $(PX4_BASE)makefiles/firmware_nuttx.mk
+endif
+ifeq ($(PX4_TARGET_OS),posix)
+include $(PX4_BASE)makefiles/firmware_posix.mk
+endif
+ifeq ($(PX4_TARGET_OS),posix-arm)
+include $(PX4_BASE)makefiles/firmware_posix.mk
+endif
+ifeq ($(PX4_TARGET_OS),qurt)
+include $(PX4_BASE)makefiles/firmware_qurt.mk
+endif
+
+#
+# Versioning
+#
+
+GIT_VER_FILE = $(PX4_VERSIONING_DIR).build_git_ver
+GIT_HEADER_FILE = $(PX4_VERSIONING_DIR)build_git_version.h
+
+$(GIT_VER_FILE) :
+	$(Q) if [ ! -f $(GIT_VER_FILE) ]; then \
+		$(MKDIR) -p $(PX4_VERSIONING_DIR); \
+		$(ECHO) "" > $(GIT_VER_FILE); \
+	fi
+
+.PHONY: checkgitversion
+checkgitversion: $(GIT_VER_FILE)
+	$(Q) if [ "$(GIT_DESC)" != "$(shell cat $(GIT_VER_FILE))" ]; then \
+		$(ECHO) "/* Auto Magically Generated file */" > $(GIT_HEADER_FILE); \
+		$(ECHO) "/* Do not edit! */" >> $(GIT_HEADER_FILE); \
+		$(ECHO) "#define PX4_GIT_VERSION_STR  \"$(GIT_DESC)\"" >> $(GIT_HEADER_FILE); \
+		$(ECHO) "#define PX4_GIT_VERSION_BINARY 0x$(GIT_DESC_SHORT)" >> $(GIT_HEADER_FILE); \
+		$(ECHO) $(GIT_DESC) > $(GIT_VER_FILE); \
+	fi
+
+#
+# Submodule Checks
+#
+
 .PHONY: checksubmodules
 checksubmodules:
 	$(Q) ($(PX4_BASE)/Tools/check_submodules.sh)
@@ -280,6 +318,7 @@ check_format:
 clean:
 	@echo > /dev/null
 	$(Q) $(RMDIR) $(BUILD_DIR)*.build
+	$(Q) $(RMDIR) $(PX4_VERSIONING_DIR)
 	$(Q) $(REMOVE) $(IMAGE_DIR)*.px4
 
 .PHONY:	distclean
diff --git a/ROMFS/px4fmu_common/init.d/rcS b/ROMFS/px4fmu_common/init.d/rcS
index 13b35313e7..8a93737ef8 100644
--- a/ROMFS/px4fmu_common/init.d/rcS
+++ b/ROMFS/px4fmu_common/init.d/rcS
@@ -101,9 +101,10 @@ then
 		fi
 	fi
 
-	if pca8574 start
-	then
-	fi
+	# Currently unused, but might be useful down the road
+	#if pca8574 start
+	#then
+	#fi
 
 	#
 	# Set default values
diff --git a/ROMFS/px4fmu_common/mixers/FX79.main.mix b/ROMFS/px4fmu_common/mixers/FX79.main.mix
index b8879af9ee..3223eff133 100755
--- a/ROMFS/px4fmu_common/mixers/FX79.main.mix
+++ b/ROMFS/px4fmu_common/mixers/FX79.main.mix
@@ -27,13 +27,13 @@ for the elevons.
 
 M: 2
 O:      10000  10000      0 -10000  10000
-S: 0 0   7500   7500      0 -10000  10000
-S: 0 1   8000   8000      0 -10000  10000
+S: 0 0   8500   8500      0 -10000  10000
+S: 0 1   9500   9500      0 -10000  10000
 
 M: 2
 O:      10000  10000      0 -10000  10000
-S: 0 0   7500   7500      0 -10000  10000
-S: 0 1  -8000  -8000      0 -10000  10000
+S: 0 0   8500   8500      0 -10000  10000
+S: 0 1  -9500  -9500      0 -10000  10000
 
 Output 2
 --------
@@ -51,19 +51,3 @@ range.  Inputs below zero are treated as zero.
 M: 1
 O:      10000  10000      0 -10000  10000
 S: 0 3      0  20000 -10000 -10000  10000
-
-Inputs to the mixer come from channel group 2 (payload), channels 0
-(bay servo 1), 1 (bay servo 2) and 3 (drop release).
------------------------------------------------------
-
-M: 1
-O:      10000  10000      0 -10000  10000
-S: 2 0  10000  10000      0 -10000  10000
-
-M: 1
-O:      10000  10000      0 -10000  10000
-S: 2 1  10000  10000      0 -10000  10000
-
-M: 1
-O:      10000  10000      0 -10000  10000
-S: 2 2 -10000 -10000      0 -10000  10000
diff --git a/makefiles/setup.mk b/makefiles/setup.mk
index 351b9f1b71..ead85e7fc9 100644
--- a/makefiles/setup.mk
+++ b/makefiles/setup.mk
@@ -55,6 +55,7 @@ export ROMFS_SRC	 = $(abspath $(PX4_BASE)/ROMFS)/
 export IMAGE_DIR	 = $(abspath $(PX4_BASE)/Images)/
 export BUILD_DIR	 = $(abspath $(PX4_BASE)/Build)/
 export ARCHIVE_DIR	 = $(abspath $(PX4_BASE)/Archives)/
+export PX4_VERSIONING_DIR = $(BUILD_DIR)versioning/
 
 #
 # Default include paths
@@ -63,7 +64,8 @@ export INCLUDE_DIRS	:= $(PX4_MODULE_SRC) \
 			   $(PX4_MODULE_SRC)/modules/ \
 			   $(PX4_INCLUDE_DIR) \
 			   $(PX4_LIB_DIR) \
-			   $(PX4_PLATFORMS_DIR)
+			   $(PX4_PLATFORMS_DIR) \
+			   $(PX4_VERSIONING_DIR)
 
 #
 # Tools
diff --git a/src/drivers/hil/hil.cpp b/src/drivers/hil/hil.cpp
index 961ec47246..a7c2e83e34 100644
--- a/src/drivers/hil/hil.cpp
+++ b/src/drivers/hil/hil.cpp
@@ -331,10 +331,9 @@ HIL::task_main()
 	/* advertise the mixed control outputs */
 	actuator_outputs_s outputs;
 	memset(&outputs, 0, sizeof(outputs));
-	/* advertise the mixed control outputs */
-	int dummy;
-	_t_outputs = orb_advertise_multi(ORB_ID(actuator_outputs),
-				   &outputs, &dummy, ORB_PRIO_LOW);
+	/* advertise the mixed control outputs, insist on the first group output */
+	_t_outputs = orb_advertise(ORB_ID(actuator_outputs),
+				   &outputs);
 
 	pollfd fds[2];
 	fds[0].fd = _t_actuators;
diff --git a/src/modules/commander/commander.cpp b/src/modules/commander/commander.cpp
index 64fd972ba4..7c15992f40 100644
--- a/src/modules/commander/commander.cpp
+++ b/src/modules/commander/commander.cpp
@@ -147,6 +147,9 @@ static constexpr uint8_t COMMANDER_MAX_GPS_NOISE = 60;		/**< Maximum percentage
 
 #define INAIR_RESTART_HOLDOFF_INTERVAL	2000000
 
+#define HIL_ID_MIN 1000
+#define HIL_ID_MAX 1999
+
 enum MAV_MODE_FLAG {
 	MAV_MODE_FLAG_CUSTOM_MODE_ENABLED = 1, /* 0b00000001 Reserved for future use. | */
 	MAV_MODE_FLAG_TEST_ENABLED = 2, /* 0b00000010 system has a test mode enabled. This flag is intended for temporary system tests and should not be used for stable implementations. | */
@@ -253,6 +256,15 @@ void *commander_low_prio_loop(void *arg);
 
 void answer_command(struct vehicle_command_s &cmd, unsigned result);
 
+/**
+ * check whether autostart ID is in the reserved range for HIL setups
+ */
+bool is_hil_setup(int id);
+
+bool is_hil_setup(int id) {
+	return (id >= HIL_ID_MIN) && (id <= HIL_ID_MAX);
+}
+
 
 int commander_main(int argc, char *argv[])
 {
@@ -437,6 +449,12 @@ transition_result_t arm_disarm(bool arm, const int mavlink_fd_local, const char
 {
 	transition_result_t arming_res = TRANSITION_NOT_CHANGED;
 
+	// For HIL platforms, require that simulated sensors are connected
+	if (is_hil_setup(autostart_id) && status.hil_state != vehicle_status_s::HIL_STATE_ON) {
+		mavlink_and_console_log_critical(mavlink_fd_local, "HIL platform: Connect to simulator before arming");
+		return TRANSITION_DENIED;
+	}
+
 	// Transition the armed state. By passing mavlink_fd to arming_state_transition it will
 	// output appropriate error messages if the state cannot transition.
 	arming_res = arming_state_transition(&status, &safety, arm ? vehicle_status_s::ARMING_STATE_ARMED : vehicle_status_s::ARMING_STATE_STANDBY, &armed,
@@ -481,10 +499,14 @@ bool handle_command(struct vehicle_status_s *status_local, const struct safety_s
 			transition_result_t hil_ret = hil_state_transition(new_hil_state, status_pub, status_local, mavlink_fd);
 
 			// Transition the arming state
-			arming_ret = arm_disarm(base_mode & MAV_MODE_FLAG_SAFETY_ARMED, mavlink_fd, "set mode command");
+			bool cmd_arm = base_mode & MAV_MODE_FLAG_SAFETY_ARMED;
+
+			arming_ret = arm_disarm(cmd_arm, mavlink_fd, "set mode command");
 
 			/* update home position on arming if at least 2s from commander start spent to avoid setting home on in-air restart */
-			if (arming_ret == TRANSITION_CHANGED && hrt_absolute_time() > commander_boot_timestamp + INAIR_RESTART_HOLDOFF_INTERVAL) {
+			if (cmd_arm && (arming_ret == TRANSITION_CHANGED) &&
+				(hrt_absolute_time() > (commander_boot_timestamp + INAIR_RESTART_HOLDOFF_INTERVAL))) {
+
 				commander_set_home_position(*home_pub, *home, *local_pos, *global_pos);
 			}
 
@@ -1156,7 +1178,11 @@ int commander_thread_main(int argc, char *argv[])
 
 	// Run preflight check
 	param_get(_param_autostart_id, &autostart_id);
-	if (autostart_id > 1999) {
+	if (is_hil_setup(autostart_id)) {
+		// HIL configuration selected: real sensors will be disabled
+		status.condition_system_sensors_initialized = false;
+		set_tune_override(TONE_STARTUP_TUNE); //normal boot tune
+	} else {
 		status.condition_system_sensors_initialized = Commander::preflightCheck(mavlink_fd, true, true, true, true, checkAirspeed, !status.rc_input_mode, !status.circuit_breaker_engaged_gpsfailure_check);
 		if (!status.condition_system_sensors_initialized) {
 			set_tune_override(TONE_GPS_WARNING_TUNE); //sensor fail tune
@@ -1164,11 +1190,6 @@ int commander_thread_main(int argc, char *argv[])
 		else {
 			set_tune_override(TONE_STARTUP_TUNE); //normal boot tune
 		}
-	} else {
-		// HIL configuration selected: real sensors will be disabled
-		warnx("HIL configuration; autostart_id: %d, onboard IMU sensors disabled", autostart_id);
-		status.condition_system_sensors_initialized = false;
-		set_tune_override(TONE_STARTUP_TUNE); //normal boot tune
 	}
 
 	commander_boot_timestamp = hrt_absolute_time();
@@ -1339,14 +1360,14 @@ int commander_thread_main(int argc, char *argv[])
 					}
 
 					/* provide RC and sensor status feedback to the user */
-					if (autostart_id > 1999) {
-						(void)Commander::preflightCheck(mavlink_fd, true, true, true, true, chAirspeed,
-								!(status.rc_input_mode == vehicle_status_s::RC_IN_MODE_OFF), !status.circuit_breaker_engaged_gpsfailure_check);
-					} else {
+					if (is_hil_setup(autostart_id)) {
 						/* HIL configuration: check only RC input */
-						warnx("new telemetry link connected: checking RC status");
 						(void)Commander::preflightCheck(mavlink_fd, false, false, false, false, false,
 								!(status.rc_input_mode == vehicle_status_s::RC_IN_MODE_OFF), false);
+					} else {
+						/* check sensors also */
+						(void)Commander::preflightCheck(mavlink_fd, true, true, true, true, chAirspeed,
+								!(status.rc_input_mode == vehicle_status_s::RC_IN_MODE_OFF), !status.circuit_breaker_engaged_gpsfailure_check);
 					}
 				}
 
@@ -2024,11 +2045,11 @@ int commander_thread_main(int argc, char *argv[])
 			}
 		}
 
-		//Get current timestamp
+		/* Get current timestamp */
 		const hrt_abstime now = hrt_absolute_time();
 
-		//First time home position update
-		if (!status.condition_home_position_valid) {
+		/* First time home position update - but only if disarmed */
+		if (!status.condition_home_position_valid && !armed.armed) {
 			commander_set_home_position(home_pub, _home, local_position, global_position);
 		}
 
diff --git a/src/modules/commander/rc_calibration.cpp b/src/modules/commander/rc_calibration.cpp
index 08261c9890..c9a8343b66 100644
--- a/src/modules/commander/rc_calibration.cpp
+++ b/src/modules/commander/rc_calibration.cpp
@@ -68,16 +68,26 @@ int do_trim_calibration(int mavlink_fd)
 
 	orb_copy(ORB_ID(manual_control_setpoint), sub_man, &sp);
 
-	/* set parameters */
-	float p = sp.y;
+	/* load trim values which are active */
+	float roll_trim_active;
+	param_get(param_find("TRIM_ROLL"), &roll_trim_active);
+	float pitch_trim_active;
+	param_get(param_find("TRIM_PITCH"), &pitch_trim_active);
+	float yaw_trim_active;
+	param_get(param_find("TRIM_YAW"), &yaw_trim_active);
+
+	/* set parameters: the new trim values are the combination of active trim values
+	   and the values coming from the remote control of the user
+	*/
+	float p = sp.y + roll_trim_active;
 	int p1r = param_set(param_find("TRIM_ROLL"), &p);
 	/*
 	 we explicitly swap sign here because the trim is added to the actuator controls
 	 which are moving in an inverse sense to manual pitch inputs
 	*/
-	p = -sp.x;
+	p = -sp.x + pitch_trim_active;
 	int p2r = param_set(param_find("TRIM_PITCH"), &p);
-	p = sp.r;
+	p = sp.r + yaw_trim_active;
 	int p3r = param_set(param_find("TRIM_YAW"), &p);
 
 	/* store to permanent storage */
diff --git a/src/modules/commander/state_machine_helper.cpp b/src/modules/commander/state_machine_helper.cpp
index 92f73ca21f..7a379612da 100644
--- a/src/modules/commander/state_machine_helper.cpp
+++ b/src/modules/commander/state_machine_helper.cpp
@@ -494,7 +494,7 @@ bool set_nav_state(struct vehicle_status_s *status, const bool data_link_loss_en
 	case vehicle_status_s::MAIN_STATE_ALTCTL:
 	case vehicle_status_s::MAIN_STATE_POSCTL:
 		/* require RC for all manual modes */
-		if ((status->rc_signal_lost || status->rc_signal_lost_cmd) && armed) {
+		if ((status->rc_signal_lost || status->rc_signal_lost_cmd) && armed && !status->condition_landed) {
 			status->failsafe = true;
 
 			if (status->condition_global_position_valid && status->condition_home_position_valid) {
diff --git a/src/modules/ekf_att_pos_estimator/ekf_att_pos_estimator_main.cpp b/src/modules/ekf_att_pos_estimator/ekf_att_pos_estimator_main.cpp
index 74d6dbadf0..b9897ffcfc 100644
--- a/src/modules/ekf_att_pos_estimator/ekf_att_pos_estimator_main.cpp
+++ b/src/modules/ekf_att_pos_estimator/ekf_att_pos_estimator_main.cpp
@@ -72,6 +72,8 @@ static constexpr float rc = 10.0f;	// RC time constant of 1st order LPF in secon
 static constexpr uint64_t FILTER_INIT_DELAY = 1 * 1000 * 1000; 	///< units: microseconds
 static constexpr float POS_RESET_THRESHOLD = 5.0f; 				///< Seconds before we signal a total GPS failure
 static constexpr unsigned MAG_SWITCH_HYSTERESIS = 10;	///< Ignore the first few mag failures (which amounts to a few milliseconds)
+static constexpr unsigned GYRO_SWITCH_HYSTERESIS = 5;	///< Ignore the first few gyro failures (which amounts to a few milliseconds)
+static constexpr unsigned ACCEL_SWITCH_HYSTERESIS = 5;	///< Ignore the first few accel failures (which amounts to a few milliseconds)
 
 /**
  * estimator app start / stop handling function
@@ -631,7 +633,10 @@ void AttitudePositionEstimatorEKF::task_main()
 				// gps sample rate is 5Hz and altitude is assumed accurate when averaged over 30 seconds
 				// maintain heavily filtered values for both baro and gps altitude
 				// Assume the filtered output should be identical for both sensors
-				_baro_gps_offset = _baro_alt_filt - _gps_alt_filt;
+
+				if (_gpsIsGood) {
+					_baro_gps_offset = _baro_alt_filt - _gps_alt_filt;
+				}
 //				if (hrt_elapsed_time(&_last_debug_print) >= 5e6) {
 //					_last_debug_print = hrt_absolute_time();
 //					perf_print_counter(_perf_baro);
@@ -658,6 +663,8 @@ void AttitudePositionEstimatorEKF::task_main()
 
 					_ekf->InitialiseFilter(initVelNED, 0.0, 0.0, 0.0f, 0.0f);
 
+					_filter_ref_offset = -_baro.altitude;
+
 					warnx("filter ref off: baro_alt: %8.4f", (double)_filter_ref_offset);
 
 				} else {
@@ -1219,7 +1226,7 @@ void AttitudePositionEstimatorEKF::pollData()
 	if (isfinite(_sensor_combined.gyro_rad_s[0]) &&
 	    isfinite(_sensor_combined.gyro_rad_s[1]) &&
 	    isfinite(_sensor_combined.gyro_rad_s[2]) &&
-	    (_sensor_combined.gyro_errcount <= _sensor_combined.gyro1_errcount)) {
+	    (_sensor_combined.gyro_errcount <= (_sensor_combined.gyro1_errcount + GYRO_SWITCH_HYSTERESIS))) {
 
 		_ekf->angRate.x = _sensor_combined.gyro_rad_s[0];
 		_ekf->angRate.y = _sensor_combined.gyro_rad_s[1];
@@ -1258,7 +1265,7 @@ void AttitudePositionEstimatorEKF::pollData()
 		int last_accel_main = _accel_main;
 
 		/* fail over to the 2nd accel if we know the first is down */
-		if (_sensor_combined.accelerometer_errcount <= _sensor_combined.accelerometer1_errcount) {
+		if (_sensor_combined.accelerometer_errcount <= (_sensor_combined.accelerometer1_errcount + ACCEL_SWITCH_HYSTERESIS)) {
 			_ekf->accel.x = _sensor_combined.accelerometer_m_s2[0];
 			_ekf->accel.y = _sensor_combined.accelerometer_m_s2[1];
 			_ekf->accel.z = _sensor_combined.accelerometer_m_s2[2];
diff --git a/src/modules/land_detector/FixedwingLandDetector.cpp b/src/modules/land_detector/FixedwingLandDetector.cpp
index 6e8393617e..5f7ded9cb2 100644
--- a/src/modules/land_detector/FixedwingLandDetector.cpp
+++ b/src/modules/land_detector/FixedwingLandDetector.cpp
@@ -85,9 +85,16 @@ bool FixedwingLandDetector::update()
 	bool landDetected = false;
 
 	if (hrt_elapsed_time(&_vehicleLocalPosition.timestamp) < 500 * 1000) {
-		_velocity_xy_filtered = 0.95f * _velocity_xy_filtered + 0.05f * sqrtf(_vehicleLocalPosition.vx *
+		float val = 0.95f * _velocity_xy_filtered + 0.05f * sqrtf(_vehicleLocalPosition.vx *
 					_vehicleLocalPosition.vx + _vehicleLocalPosition.vy * _vehicleLocalPosition.vy);
-		_velocity_z_filtered = 0.95f * _velocity_z_filtered + 0.05f * fabsf(_vehicleLocalPosition.vz);
+		if (isfinite(val)) {
+			_velocity_xy_filtered = val;
+		}
+		val = 0.95f * _velocity_z_filtered + 0.05f * fabsf(_vehicleLocalPosition.vz);
+
+		if (isfinite(val)) {
+			_velocity_z_filtered = val;
+		}
 	}
 
 	if (hrt_elapsed_time(&_airspeed.timestamp) < 500 * 1000) {
diff --git a/src/modules/mavlink/mavlink_receiver.cpp b/src/modules/mavlink/mavlink_receiver.cpp
index 7ede93ec2d..1a6494ad93 100644
--- a/src/modules/mavlink/mavlink_receiver.cpp
+++ b/src/modules/mavlink/mavlink_receiver.cpp
@@ -621,7 +621,7 @@ MavlinkReceiver::handle_message_set_position_target_local_ned(mavlink_message_t
 					}
 
 					/* set the yaw sp value */
-					if (!offboard_control_mode.ignore_attitude) {
+					if (!offboard_control_mode.ignore_attitude && !isnan(set_position_target_local_ned.yaw)) {
 						pos_sp_triplet.current.yaw_valid = true;
 						pos_sp_triplet.current.yaw = set_position_target_local_ned.yaw;
 
@@ -630,7 +630,7 @@ MavlinkReceiver::handle_message_set_position_target_local_ned(mavlink_message_t
 					}
 
 					/* set the yawrate sp value */
-					if (!offboard_control_mode.ignore_bodyrate) {
+					if (!offboard_control_mode.ignore_bodyrate && !isnan(set_position_target_local_ned.yaw)) {
 						pos_sp_triplet.current.yawspeed_valid = true;
 						pos_sp_triplet.current.yawspeed = set_position_target_local_ned.yaw_rate;
 
diff --git a/src/modules/mc_pos_control/mc_pos_control_params.c b/src/modules/mc_pos_control/mc_pos_control_params.c
index fc73b31f59..ade43ffb91 100644
--- a/src/modules/mc_pos_control/mc_pos_control_params.c
+++ b/src/modules/mc_pos_control/mc_pos_control_params.c
@@ -55,13 +55,16 @@ PARAM_DEFINE_FLOAT(MPC_THR_MIN, 0.1f);
 /**
  * Maximum thrust
  *
- * Limit max allowed thrust.
+ * Limit max allowed thrust. Setting a value of one can put
+ * the system into actuator saturation as no spread between
+ * the motors is possible any more. A value of 0.8 - 0.9
+ * is recommended.
  *
  * @min 0.0
  * @max 1.0
  * @group Multicopter Position Control
  */
-PARAM_DEFINE_FLOAT(MPC_THR_MAX, 1.0f);
+PARAM_DEFINE_FLOAT(MPC_THR_MAX, 0.9f);
 
 /**
  * Proportional gain for vertical position error
diff --git a/src/modules/navigator/mission.cpp b/src/modules/navigator/mission.cpp
index 98b01c7578..fe876ee8b1 100644
--- a/src/modules/navigator/mission.cpp
+++ b/src/modules/navigator/mission.cpp
@@ -230,9 +230,9 @@ Mission::update_offboard_mission()
 		 * however warnings are issued to the gcs via mavlink from inside the MissionFeasiblityChecker */
 		dm_item_t dm_current = DM_KEY_WAYPOINTS_OFFBOARD(_offboard_mission.dataman_id);
 
-		failed = !_missionFeasiblityChecker.checkMissionFeasible(_navigator->get_vstatus()->is_rotary_wing,
+		failed = !_missionFeasiblityChecker.checkMissionFeasible(_navigator->get_mavlink_fd(), _navigator->get_vstatus()->is_rotary_wing,
 				dm_current, (size_t) _offboard_mission.count, _navigator->get_geofence(),
-				_navigator->get_home_position()->alt);
+				_navigator->get_home_position()->alt, _navigator->home_position_valid());
 
 	} else {
 		warnx("offboard mission update failed");
@@ -271,6 +271,16 @@ Mission::advance_mission()
 	}
 }
 
+int
+Mission::get_absolute_altitude_for_item(struct mission_item_s &mission_item)
+{
+	if (_mission_item.altitude_is_relative) {
+		return _mission_item.altitude + _navigator->get_home_position()->alt;
+	} else {
+		return _mission_item.altitude;
+	}
+}
+
 bool
 Mission::check_dist_1wp()
 {
@@ -354,7 +364,7 @@ Mission::set_mission_items()
 
 	/* Copy previous mission item altitude (can be extended to a copy of the full mission item if needed) */
 	if (pos_sp_triplet->previous.valid) {
-		_mission_item_previous_alt = _mission_item.altitude;
+		_mission_item_previous_alt = get_absolute_altitude_for_item(_mission_item);
 	}
 
 	/* get home distance state */
@@ -374,13 +384,14 @@ Mission::set_mission_items()
 	} else if (home_dist_ok && read_mission_item(false, true, &_mission_item)) {
 		/* if mission type changed, notify */
 		if (_mission_type != MISSION_TYPE_OFFBOARD) {
-			mavlink_log_critical(_navigator->get_mavlink_fd(), "offboard mission now running");
+			mavlink_log_info(_navigator->get_mavlink_fd(), "offboard mission now running");
 		}
 		_mission_type = MISSION_TYPE_OFFBOARD;
 	} else {
 		/* no mission available or mission finished, switch to loiter */
 		if (_mission_type != MISSION_TYPE_NONE) {
-			mavlink_log_critical(_navigator->get_mavlink_fd(), "mission finished");
+			/* https://en.wikipedia.org/wiki/Loiter_(aeronautics) */
+			mavlink_log_critical(_navigator->get_mavlink_fd(), "mission finished, loitering");
 
 			/* use last setpoint for loiter */
 			_navigator->set_can_loiter_at_sp(true);
@@ -388,8 +399,9 @@ Mission::set_mission_items()
 		} else if (!user_feedback_done) {
 			/* only tell users that we got no mission if there has not been any
 			 * better, more specific feedback yet
+			 * https://en.wikipedia.org/wiki/Loiter_(aeronautics)
 			 */
-			mavlink_log_critical(_navigator->get_mavlink_fd(), "no valid mission available");
+			mavlink_log_critical(_navigator->get_mavlink_fd(), "no valid mission available, loitering");
 		}
 		_mission_type = MISSION_TYPE_NONE;
 
@@ -440,10 +452,7 @@ Mission::set_mission_items()
 		mission_item_to_position_setpoint(&_mission_item, &pos_sp_triplet->next);
 
 		/* calculate takeoff altitude */
-		float takeoff_alt = _mission_item.altitude;
-		if (_mission_item.altitude_is_relative) {
-			takeoff_alt += _navigator->get_home_position()->alt;
-		}
+		float takeoff_alt = get_absolute_altitude_for_item(_mission_item);
 
 		/* takeoff to at least NAV_TAKEOFF_ALT above home/ground, even if first waypoint is lower */
 		if (_navigator->get_vstatus()->condition_landed) {
@@ -609,14 +618,14 @@ Mission::altitude_sp_foh_update()
 	/* if the minimal distance is smaller then the acceptance radius, we should be at waypoint alt
 	 * navigator will soon switch to the next waypoint item (if there is one) as soon as we reach this altitude */
 	if (_min_current_sp_distance_xy < _navigator->get_acceptance_radius(_mission_item.acceptance_radius)) {
-		pos_sp_triplet->current.alt = _mission_item.altitude;
+		pos_sp_triplet->current.alt = get_absolute_altitude_for_item(_mission_item);
 	} else {
 		/* update the altitude sp of the 'current' item in the sp triplet, but do not update the altitude sp
 		* of the mission item as it is used to check if the mission item is reached
 		* The setpoint is set linearly and such that the system reaches the current altitude at the acceptance
 		* radius around the current waypoint
 		**/
-		float delta_alt = (_mission_item.altitude - _mission_item_previous_alt);
+		float delta_alt = (get_absolute_altitude_for_item(_mission_item) - _mission_item_previous_alt);
 		float grad = -delta_alt/(_distance_current_previous - _navigator->get_acceptance_radius(_mission_item.acceptance_radius));
 		float a = _mission_item_previous_alt - grad * _distance_current_previous;
 		pos_sp_triplet->current.alt = a + grad * _min_current_sp_distance_xy;
diff --git a/src/modules/navigator/mission.h b/src/modules/navigator/mission.h
index e9f78e8fdc..bc9a2c6c82 100644
--- a/src/modules/navigator/mission.h
+++ b/src/modules/navigator/mission.h
@@ -132,6 +132,8 @@ private:
 	 */
 	void altitude_sp_foh_reset();
 
+	int get_absolute_altitude_for_item(struct mission_item_s &mission_item);
+
 	/**
 	 * Read current or next mission item from the dataman and watch out for DO_JUMPS
 	 * @return true if successful
diff --git a/src/modules/navigator/mission_feasibility_checker.cpp b/src/modules/navigator/mission_feasibility_checker.cpp
index d9297f25bf..9d1dc7c7e6 100644
--- a/src/modules/navigator/mission_feasibility_checker.cpp
+++ b/src/modules/navigator/mission_feasibility_checker.cpp
@@ -63,42 +63,43 @@ MissionFeasibilityChecker::MissionFeasibilityChecker() : _mavlink_fd(-1), _capab
 }
 
 
-bool MissionFeasibilityChecker::checkMissionFeasible(bool isRotarywing, dm_item_t dm_current, size_t nMissionItems, Geofence &geofence, float home_alt)
+bool MissionFeasibilityChecker::checkMissionFeasible(int mavlink_fd, bool isRotarywing, dm_item_t dm_current, size_t nMissionItems, Geofence &geofence, float home_alt, bool home_valid)
 {
 	bool failed = false;
 	/* Init if not done yet */
 	init();
 
-	/* Open mavlink fd */
-	if (_mavlink_fd < 0) {
-		/* try to open the mavlink log device every once in a while */
-		_mavlink_fd = open(MAVLINK_LOG_DEVICE, 0);
-	}
+	_mavlink_fd = mavlink_fd;
 
 	// check if all mission item commands are supported
 	failed |= !checkMissionItemValidity(dm_current, nMissionItems);
 
 
-	if (isRotarywing)
-		failed |= !checkMissionFeasibleRotarywing(dm_current, nMissionItems, geofence, home_alt);
-	else
-		failed |= !checkMissionFeasibleFixedwing(dm_current, nMissionItems, geofence, home_alt);
+	if (isRotarywing) {
+		failed |= !checkMissionFeasibleRotarywing(dm_current, nMissionItems, geofence, home_alt, home_valid);
+	} else {
+		failed |= !checkMissionFeasibleFixedwing(dm_current, nMissionItems, geofence, home_alt, home_valid);
+	}
+
+	if (!failed) {
+		mavlink_log_info(_mavlink_fd, "Mission checked and ready.");
+	}
 
 	return !failed;
 }
 
-bool MissionFeasibilityChecker::checkMissionFeasibleRotarywing(dm_item_t dm_current, size_t nMissionItems, Geofence &geofence, float home_alt)
+bool MissionFeasibilityChecker::checkMissionFeasibleRotarywing(dm_item_t dm_current, size_t nMissionItems, Geofence &geofence, float home_alt, bool home_valid)
 {
 
 	/* Perform checks and issue feedback to the user for all checks */
 	bool resGeofence = checkGeofence(dm_current, nMissionItems, geofence);
-	bool resHomeAltitude = checkHomePositionAltitude(dm_current, nMissionItems, home_alt);
+	bool resHomeAltitude = checkHomePositionAltitude(dm_current, nMissionItems, home_alt, home_valid);
 
 	/* Mission is only marked as feasible if all checks return true */
 	return (resGeofence && resHomeAltitude);
 }
 
-bool MissionFeasibilityChecker::checkMissionFeasibleFixedwing(dm_item_t dm_current, size_t nMissionItems, Geofence &geofence, float home_alt)
+bool MissionFeasibilityChecker::checkMissionFeasibleFixedwing(dm_item_t dm_current, size_t nMissionItems, Geofence &geofence, float home_alt, bool home_valid)
 {
 	/* Update fixed wing navigation capabilites */
 	updateNavigationCapabilities();
@@ -107,7 +108,7 @@ bool MissionFeasibilityChecker::checkMissionFeasibleFixedwing(dm_item_t dm_curre
 	/* Perform checks and issue feedback to the user for all checks */
 	bool resLanding = checkFixedWingLanding(dm_current, nMissionItems);
 	bool resGeofence = checkGeofence(dm_current, nMissionItems, geofence);
-	bool resHomeAltitude = checkHomePositionAltitude(dm_current, nMissionItems, home_alt);
+	bool resHomeAltitude = checkHomePositionAltitude(dm_current, nMissionItems, home_alt, home_valid);
 
 	/* Mission is only marked as feasible if all checks return true */
 	return (resLanding && resGeofence && resHomeAltitude);
@@ -136,7 +137,7 @@ bool MissionFeasibilityChecker::checkGeofence(dm_item_t dm_current, size_t nMiss
 	return true;
 }
 
-bool MissionFeasibilityChecker::checkHomePositionAltitude(dm_item_t dm_current, size_t nMissionItems, float home_alt, bool throw_error)
+bool MissionFeasibilityChecker::checkHomePositionAltitude(dm_item_t dm_current, size_t nMissionItems, float home_alt, bool home_valid, bool throw_error)
 {
 	/* Check if all all waypoints are above the home altitude, only return false if bool throw_error = true */
 	for (size_t i = 0; i < nMissionItems; i++) {
@@ -152,6 +153,12 @@ bool MissionFeasibilityChecker::checkHomePositionAltitude(dm_item_t dm_current,
 			}
 		}
 
+		/* always reject relative alt without home set */
+		if (missionitem.altitude_is_relative && !home_valid) {
+			mavlink_log_critical(_mavlink_fd, "Rejecting Mission: No home pos, WP %d uses rel alt", i);
+			return false;
+		}
+
 		/* calculate the global waypoint altitude */
 		float wp_alt = (missionitem.altitude_is_relative) ? missionitem.altitude + home_alt : missionitem.altitude;
 
@@ -197,7 +204,6 @@ bool MissionFeasibilityChecker::checkMissionItemValidity(dm_item_t dm_current, s
 			return false;
 		}
 	}
-	mavlink_log_info(_mavlink_fd, "Mission ready.");
 	return true;
 }
 
diff --git a/src/modules/navigator/mission_feasibility_checker.h b/src/modules/navigator/mission_feasibility_checker.h
index 94b6b29226..9c9511be3d 100644
--- a/src/modules/navigator/mission_feasibility_checker.h
+++ b/src/modules/navigator/mission_feasibility_checker.h
@@ -61,16 +61,16 @@ private:
 
 	/* Checks for all airframes */
 	bool checkGeofence(dm_item_t dm_current, size_t nMissionItems, Geofence &geofence);
-	bool checkHomePositionAltitude(dm_item_t dm_current, size_t nMissionItems, float home_alt, bool throw_error = false);
+	bool checkHomePositionAltitude(dm_item_t dm_current, size_t nMissionItems, float home_alt, bool home_valid, bool throw_error = false);
 	bool checkMissionItemValidity(dm_item_t dm_current, size_t nMissionItems);
 
 	/* Checks specific to fixedwing airframes */
-	bool checkMissionFeasibleFixedwing(dm_item_t dm_current, size_t nMissionItems, Geofence &geofence, float home_alt);
+	bool checkMissionFeasibleFixedwing(dm_item_t dm_current, size_t nMissionItems, Geofence &geofence, float home_alt, bool home_valid);
 	bool checkFixedWingLanding(dm_item_t dm_current, size_t nMissionItems);
 	void updateNavigationCapabilities();
 
 	/* Checks specific to rotarywing airframes */
-	bool checkMissionFeasibleRotarywing(dm_item_t dm_current, size_t nMissionItems, Geofence &geofence, float home_alt);
+	bool checkMissionFeasibleRotarywing(dm_item_t dm_current, size_t nMissionItems, Geofence &geofence, float home_alt, bool home_valid);
 public:
 
 	MissionFeasibilityChecker();
@@ -79,8 +79,8 @@ public:
 	/*
 	 * Returns true if mission is feasible and false otherwise
 	 */
-	bool checkMissionFeasible(bool isRotarywing, dm_item_t dm_current, size_t nMissionItems, Geofence &geofence,
-				  float home_alt);
+	bool checkMissionFeasible(int mavlink_fd, bool isRotarywing, dm_item_t dm_current, size_t nMissionItems, Geofence &geofence,
+				  float home_alt, bool home_valid);
 
 };
 
diff --git a/src/modules/navigator/navigator.h b/src/modules/navigator/navigator.h
index 95e3f9f964..782a297fbb 100644
--- a/src/modules/navigator/navigator.h
+++ b/src/modules/navigator/navigator.h
@@ -134,6 +134,7 @@ public:
 	struct vehicle_gps_position_s*	    get_gps_position() { return &_gps_pos; }
 	struct sensor_combined_s*	    get_sensor_combined() { return &_sensor_combined; }
 	struct home_position_s*		    get_home_position() { return &_home_pos; }
+	bool				    home_position_valid() { return _home_position_set; }
 	struct position_setpoint_triplet_s* get_position_setpoint_triplet() { return &_pos_sp_triplet; }
 	struct mission_result_s*	    get_mission_result() { return &_mission_result; }
 	struct geofence_result_s*		    get_geofence_result() { return &_geofence_result; }
diff --git a/src/modules/navigator/navigator_main.cpp b/src/modules/navigator/navigator_main.cpp
index 97baa1235f..8cfce50879 100644
--- a/src/modules/navigator/navigator_main.cpp
+++ b/src/modules/navigator/navigator_main.cpp
@@ -209,7 +209,10 @@ Navigator::home_position_update()
 
 	if (updated) {
 		orb_copy(ORB_ID(home_position), _home_pos_sub, &_home_pos);
-		_home_position_set = true;
+
+		if (_home_pos.timestamp > 0) {
+			_home_position_set = true;
+		}
 	}
 }
 
diff --git a/src/modules/px4iofirmware/mixer.cpp b/src/modules/px4iofirmware/mixer.cpp
index 596064f15f..5e6a3a585a 100644
--- a/src/modules/px4iofirmware/mixer.cpp
+++ b/src/modules/px4iofirmware/mixer.cpp
@@ -311,13 +311,6 @@ mixer_callback(uintptr_t handle,
 	case MIX_FMU:
 		if (control_index < PX4IO_CONTROL_CHANNELS && control_group < PX4IO_CONTROL_GROUPS ) {
 			control = REG_TO_FLOAT(r_page_controls[CONTROL_PAGE_INDEX(control_group, control_index)]);
-			if (control_group == 0 && control_index == 0) {
-				control += REG_TO_FLOAT(r_setup_trim_roll);
-			} else if (control_group == 0 && control_index == 1) {
-				control += REG_TO_FLOAT(r_setup_trim_pitch);
-			} else if (control_group == 0 && control_index == 2) {
-				control += REG_TO_FLOAT(r_setup_trim_yaw);
-			}
 			break;
 		}
 		return -1;
@@ -360,6 +353,13 @@ mixer_callback(uintptr_t handle,
 		return -1;
 	}
 
+	/* limit output */
+	if (control > 1.0f) {
+		control = 1.0f;
+	} else if (control < -1.0f) {
+		control = -1.0f;
+	}
+
 	return 0;
 }
 
diff --git a/src/modules/sensors/sensor_params.c b/src/modules/sensors/sensor_params.c
index 1bebea2060..7b3932638b 100644
--- a/src/modules/sensors/sensor_params.c
+++ b/src/modules/sensors/sensor_params.c
@@ -1285,7 +1285,7 @@ PARAM_DEFINE_FLOAT(RC_AUTO_TH, 0.75f);
  *
  * @min -1
  * @max 1
- *
+ * @group Radio Switches
  *
  */
 PARAM_DEFINE_FLOAT(RC_POSCTL_TH, 0.5f);
diff --git a/src/modules/systemlib/git_version.h b/src/modules/systemlib/git_version.h
index 9b8f9e860e..5f8d411088 100644
--- a/src/modules/systemlib/git_version.h
+++ b/src/modules/systemlib/git_version.h
@@ -41,6 +41,8 @@
 
 #include <stdint.h>
 
+#include "build_git_version.h"
+
 __BEGIN_DECLS
 
 __EXPORT extern const char* px4_git_version;
diff --git a/src/modules/systemlib/module.mk b/src/modules/systemlib/module.mk
index ff409fa473..f80d8009ae 100644
--- a/src/modules/systemlib/module.mk
+++ b/src/modules/systemlib/module.mk
@@ -56,7 +56,7 @@ SRCS		 = err.c \
 		   circuit_breaker.cpp \
 		   circuit_breaker_params.c \
 		   mcu_version.c \
-		   $(BUILD_DIR)git_version.c
+		   circuit_breaker_params.c
 
 MAXOPTIMIZATION	 = -Os
 
diff --git a/src/platforms/ros/nodes/mavlink/mavlink.cpp b/src/platforms/ros/nodes/mavlink/mavlink.cpp
index 2758979a29..c92dd0843d 100644
--- a/src/platforms/ros/nodes/mavlink/mavlink.cpp
+++ b/src/platforms/ros/nodes/mavlink/mavlink.cpp
@@ -273,7 +273,7 @@ void Mavlink::handle_msg_set_position_target_local_ned(const mavlink_message_t *
 		}
 
 		/* set the yaw sp value */
-		if (!offboard_control_mode.ignore_attitude) {
+		if (!offboard_control_mode.ignore_attitude && !isnan(set_position_target_local_ned.yaw)) {
 			pos_sp_triplet.current.yaw_valid = true;
 			pos_sp_triplet.current.yaw = set_position_target_local_ned.yaw;
 
@@ -282,7 +282,7 @@ void Mavlink::handle_msg_set_position_target_local_ned(const mavlink_message_t *
 		}
 
 		/* set the yawrate sp value */
-		if (!offboard_control_mode.ignore_bodyrate) {
+		if (!offboard_control_mode.ignore_bodyrate && !isnan(set_position_target_local_ned.yaw)) {
 			pos_sp_triplet.current.yawspeed_valid = true;
 			pos_sp_triplet.current.yawspeed = set_position_target_local_ned.yaw_rate;
 
diff --git a/src/systemcmds/ver/ver.c b/src/systemcmds/ver/ver.c
index a248dfb79c..caac93024a 100644
--- a/src/systemcmds/ver/ver.c
+++ b/src/systemcmds/ver/ver.c
@@ -57,6 +57,9 @@ static const char sz_ver_all_str[] 	= "all";
 static const char mcu_ver_str[]		= "mcu";
 static const char mcu_uid_str[]		= "uid";
 
+const char* px4_git_version = PX4_GIT_VERSION_STR;
+const uint64_t px4_git_version_binary = PX4_GIT_VERSION_BINARY;
+
 static void usage(const char *reason)
 {
 	if (reason != NULL) {