diff --git a/src/platforms/common/stm32/timing_stm32.c b/src/platforms/common/stm32/timing_stm32.c
index 0f6edf53d4e..9a94364bc76 100644
--- a/src/platforms/common/stm32/timing_stm32.c
+++ b/src/platforms/common/stm32/timing_stm32.c
@@ -21,6 +21,7 @@
 #include "general.h"
 #include "platform.h"
 #include "morse.h"
+#include "usb.h"
 
 #include <libopencm3/cm3/systick.h>
 #include <libopencm3/cm3/nvic.h>
@@ -44,6 +45,18 @@ static uint8_t monitor_ticks = 0;
 #define ADC_VREFINT_MIN 1404U
 #endif
 
+static void usb_config_morse_msg_update(void)
+{
+	if (usb_config_is_updated()) {
+		if (usb_config == 0)
+			morse("NO USB HOST.", true);
+		else
+			morse(NULL, false);
+
+		usb_config_clear_updated();
+	}
+}
+
 void platform_timing_init(void)
 {
 	/* Setup heartbeat timer */
@@ -71,6 +84,7 @@ void sys_tick_handler(void)
 	if (morse_tick >= MORSECNT) {
 		if (running_status)
 			gpio_toggle(LED_PORT, LED_IDLE_RUN);
+		usb_config_morse_msg_update();
 		SET_ERROR_STATE(morse_update());
 		morse_tick = 0;
 	} else
diff --git a/src/platforms/common/usb.c b/src/platforms/common/usb.c
index 882d7b88fb5..7baa04d8cf4 100644
--- a/src/platforms/common/usb.c
+++ b/src/platforms/common/usb.c
@@ -40,6 +40,15 @@ static uint8_t usbd_control_buffer[512];
  * to fit your EP0 transactions.
  */
 
+static bool usb_config_updated = true;
+
+static void usb_config_set_updated(usbd_device *const dev, const uint16_t value)
+{
+	(void)dev;
+	(void)value;
+	usb_config_updated = true;
+}
+
 void blackmagic_usb_init(void)
 {
 	read_serial_number();
@@ -51,6 +60,7 @@ void blackmagic_usb_init(void)
 	microsoft_os_register_descriptor_sets(usbdev, microsoft_os_descriptor_sets, DESCRIPTOR_SETS);
 	usbd_register_set_config_callback(usbdev, usb_serial_set_config);
 	usbd_register_set_config_callback(usbdev, dfu_set_config);
+	usbd_register_set_config_callback(usbdev, usb_config_set_updated);
 
 	nvic_set_priority(USB_IRQ, IRQ_PRI_USB);
 	nvic_enable_irq(USB_IRQ);
@@ -65,3 +75,13 @@ void USB_ISR(void)
 {
 	usbd_poll(usbdev);
 }
+
+bool usb_config_is_updated(void)
+{
+	return usb_config_updated;
+}
+
+void usb_config_clear_updated(void)
+{
+	usb_config_updated = false;
+}
diff --git a/src/platforms/common/usb.h b/src/platforms/common/usb.h
index 4693829ef6d..336d075b2f3 100644
--- a/src/platforms/common/usb.h
+++ b/src/platforms/common/usb.h
@@ -58,4 +58,10 @@ void blackmagic_usb_init(void);
 /* Returns current usb configuration, or 0 if not configured. */
 uint16_t usb_get_config(void);
 
+/* Returns true if usb config has been updated. */
+bool usb_config_is_updated(void);
+
+/* Clears usb config updated flag. */
+void usb_config_clear_updated(void);
+
 #endif /* PLATFORMS_COMMON_USB_H */