diff --git a/ArduCopter/Parameters.h b/ArduCopter/Parameters.h
index c52e732ea3..ce9278ed85 100644
--- a/ArduCopter/Parameters.h
+++ b/ArduCopter/Parameters.h
@@ -419,7 +419,7 @@ public:
     AP_Int16        throttle_behavior;
     AP_Float        pilot_takeoff_alt;
 
-    AP_Int16        rtl_altitude;
+    AP_Int32        rtl_altitude;
     AP_Int16        rtl_speed_cms;
     AP_Float        rtl_cone_slope;
 #if RANGEFINDER_ENABLED == ENABLED
diff --git a/ArduCopter/esc_calibration.cpp b/ArduCopter/esc_calibration.cpp
index 88c1e88ed4..c27c93978b 100644
--- a/ArduCopter/esc_calibration.cpp
+++ b/ArduCopter/esc_calibration.cpp
@@ -118,7 +118,7 @@ void Copter::esc_calibration_auto()
 
     // delay for 5 seconds while outputting pulses
     uint32_t tstart = millis();
-    while (millis() - tstart < 5000) {
+    while (millis() - tstart < 3000) {
         SRV_Channels::cork();
         motors->set_throttle_passthrough_for_esc_calibration(1.0f);
         SRV_Channels::push();
diff --git a/libraries/AP_Camera/AP_Camera.cpp b/libraries/AP_Camera/AP_Camera.cpp
index 13e01790d8..6e9d80e7c8 100644
--- a/libraries/AP_Camera/AP_Camera.cpp
+++ b/libraries/AP_Camera/AP_Camera.cpp
@@ -487,7 +487,7 @@ void AP_Camera::uavcan_pic()
         //altitude_rel = current_loc.alt - ahrs.get_home().alt;
     }
 
-    gcs().send_text(MAV_SEVERITY_INFO, "alt:%f", camera_can_msg.alt);
+    // gcs().send_text(MAV_SEVERITY_INFO, "alt:%f", camera_can_msg.alt);
     camera_can_msg.pitch = ahrs.pitch_sensor * 1e-2f;
     camera_can_msg.roll = ahrs.roll_sensor * 1e-2f;
     camera_can_msg.yaw = ahrs.yaw_sensor * 1e-2f;
diff --git a/modules/mavlink b/modules/mavlink
index 0013b46db8..18cab69509 160000
--- a/modules/mavlink
+++ b/modules/mavlink
@@ -1 +1 @@
-Subproject commit 0013b46db8cb437b6ad77d736263597d90a2262d
+Subproject commit 18cab6950986cd7b9b7a507ec35f3501d4a7e019