diff --git a/nuttx-configs/px4fmu-v5/nsh/defconfig b/nuttx-configs/px4fmu-v5/nsh/defconfig
index bc25a9f1abaa..897d3e1723cf 100644
--- a/nuttx-configs/px4fmu-v5/nsh/defconfig
+++ b/nuttx-configs/px4fmu-v5/nsh/defconfig
@@ -962,7 +962,7 @@ CONFIG_CDCACM_NRDREQS=4
 CONFIG_CDCACM_NWRREQS=4
 CONFIG_CDCACM_BULKIN_REQLEN=96
 CONFIG_CDCACM_RXBUFSIZE=600
-CONFIG_CDCACM_TXBUFSIZE=8000
+CONFIG_CDCACM_TXBUFSIZE=12000
 CONFIG_CDCACM_VENDORID=0x26ac
 CONFIG_CDCACM_PRODUCTID=0x0032
 CONFIG_CDCACM_VENDORSTR="3D Robotics"
diff --git a/src/modules/mavlink/mavlink_main.cpp b/src/modules/mavlink/mavlink_main.cpp
index aa441951a927..0b90d4583f40 100644
--- a/src/modules/mavlink/mavlink_main.cpp
+++ b/src/modules/mavlink/mavlink_main.cpp
@@ -1988,9 +1988,6 @@ Mavlink::task_main(int argc, char *argv[])
 	/* Initialize system properties */
 	mavlink_update_system();
 
-	/* start the MAVLink receiver */
-	MavlinkReceiver::receive_start(&_receive_thread, this);
-
 	MavlinkOrbSubscription *param_sub = add_orb_subscription(ORB_ID(parameter_update));
 	uint64_t param_time = 0;
 	MavlinkOrbSubscription *status_sub = add_orb_subscription(ORB_ID(vehicle_status));
@@ -2180,6 +2177,9 @@ Mavlink::task_main(int argc, char *argv[])
 		send_autopilot_capabilites();
 	}
 
+	/* start the MAVLink receiver last to avoid a race */
+	MavlinkReceiver::receive_start(&_receive_thread, this);
+
 	while (!_task_should_exit) {
 		/* main loop */
 		usleep(_main_loop_delay);