diff --git a/boards/px4/fmu-v6x/nuttx-config/nsh/defconfig b/boards/px4/fmu-v6x/nuttx-config/nsh/defconfig
index 87c8a46f04..1304d2fb9c 100644
--- a/boards/px4/fmu-v6x/nuttx-config/nsh/defconfig
+++ b/boards/px4/fmu-v6x/nuttx-config/nsh/defconfig
@@ -75,6 +75,7 @@ CONFIG_BOARD_ASSERT_RESET_VALUE=0
 CONFIG_BOARD_CRASHDUMP=y
 CONFIG_BOARD_LOOPSPERMSEC=95751
 CONFIG_BOARD_RESET_ON_ASSERT=2
+CONFIG_BOARD_USE_PROBES=y
 CONFIG_BUILTIN=y
 CONFIG_CDCACM=y
 CONFIG_CDCACM_IFLOWCONTROL=y
diff --git a/platforms/nuttx/NuttX/nuttx b/platforms/nuttx/NuttX/nuttx
index b25bc43cd8..2b59c49de7 160000
--- a/platforms/nuttx/NuttX/nuttx
+++ b/platforms/nuttx/NuttX/nuttx
@@ -1 +1 @@
-Subproject commit b25bc43cd81e257c5e63ac17c7c4331510584af6
+Subproject commit 2b59c49de79a73511b70ed9c00f239fec9333118
diff --git a/src/drivers/pwm_out/PWMOut.cpp b/src/drivers/pwm_out/PWMOut.cpp
index 6b482a36f7..657296d70c 100644
--- a/src/drivers/pwm_out/PWMOut.cpp
+++ b/src/drivers/pwm_out/PWMOut.cpp
@@ -332,5 +332,7 @@ px4io driver is used for main ones.
 
 extern "C" __EXPORT int pwm_out_main(int argc, char *argv[])
 {
+  PROBE_INIT(0x1ff);
+  return 0;
 	return PWMOut::main(argc, argv);
 }
diff --git a/src/modules/mavlink/mavlink_main.cpp b/src/modules/mavlink/mavlink_main.cpp
index bb26398ba9..947778663d 100644
--- a/src/modules/mavlink/mavlink_main.cpp
+++ b/src/modules/mavlink/mavlink_main.cpp
@@ -766,7 +766,9 @@ void Mavlink::send_finish()
 
 	// send message to UART
 	if (get_protocol() == Protocol::SERIAL) {
+		PROBE(8, 0);
 		ret = ::write(_uart_fd, _buf, _buf_fill);
+		PROBE(8, 1);
 	}
 
 #if defined(MAVLINK_UDP)