diff --git a/os/arch/arm/src/amebad/amebad_serial.c b/os/arch/arm/src/amebad/amebad_serial.c
index 47cf1ed699..f546977b7a 100644
--- a/os/arch/arm/src/amebad/amebad_serial.c
+++ b/os/arch/arm/src/amebad/amebad_serial.c
@@ -481,7 +481,7 @@ void rtl8721d_uart_irq(uint32_t id, SerialIrq event)
 	}
 	if (event == TxIrq) {
 		priv->tx_level = TX_FIFO_MAX;
-		uart_xmitchars(dev);
+		(void)uart_xmitchars(dev);
 		priv->tx_level = 0;
 	}
 }
diff --git a/os/arch/arm/src/amebalite/amebalite_serial.c b/os/arch/arm/src/amebalite/amebalite_serial.c
index 1ff79cf910..c40af0e6e2 100644
--- a/os/arch/arm/src/amebalite/amebalite_serial.c
+++ b/os/arch/arm/src/amebalite/amebalite_serial.c
@@ -748,7 +748,7 @@ static void rtl8720e_log_up_txint(struct uart_dev_s *dev, bool enable)
 	priv->txint_enable = enable;
 
 	if (enable)
-		uart_xmitchars(dev);
+		(void)uart_xmitchars(dev);
 		//LOGUART_RxCmd(LOGUART_DEV, ENABLE);
 	//else
 		//LOGUART_RxCmd(LOGUART_DEV, DISABLE);
@@ -891,7 +891,7 @@ void rtl8720e_uart_irq(uint32_t id, SerialIrq event)
 	}
 	if (event == TxIrq) {
 		priv->tx_level = TX_FIFO_MAX;
-		uart_xmitchars(dev);
+		(void)uart_xmitchars(dev);
 		priv->tx_level = 0;
 	}
 }
diff --git a/os/arch/arm/src/amebasmart/amebasmart_serial.c b/os/arch/arm/src/amebasmart/amebasmart_serial.c
index 33b0b0b81e..9e4106d2c2 100644
--- a/os/arch/arm/src/amebasmart/amebasmart_serial.c
+++ b/os/arch/arm/src/amebasmart/amebasmart_serial.c
@@ -512,6 +512,9 @@ static uart_dev_t g_uart4port = {
 };
 #endif
 
+#ifdef CONFIG_UART4_SERIAL_CONSOLE
+static bool g_log_flush_running;
+#endif
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
@@ -573,7 +576,7 @@ static int rtl8730e_log_uart_irq(void *Data)
 
 	u32 txempty_en = LOGUART_GET_ETPFEI(IrqEn);
 	if ((txempty_en == 0x4 && (reg_lsr & LOGUART_BIT_TP4F_EMPTY)) || (reg_lsr & LOGUART_BIT_TP4F_NOT_FULL)) {
-		uart_xmitchars(&CONSOLE_DEV);
+		(void)uart_xmitchars(&CONSOLE_DEV);
 	}
 	return 0;
 }
@@ -921,7 +924,7 @@ void rtl8730e_uart_irq(uint32_t id, SerialIrq event)
 	}
 	if (event == TxIrq) {
 		priv->tx_level = TX_FIFO_MAX;
-		uart_xmitchars(dev);
+		(void)uart_xmitchars(dev);
 		priv->tx_level = 0;
 	}
 }
@@ -1377,6 +1380,44 @@ int up_getc(void)
 	return ch;
 }
 
+/****************************************************************************
+ * Name: up_flush_console
+ *
+ * Description:
+ *    This function is used to ensure that all characters in the UART buffer
+ *    are transmitted.
+ *
+ * Input Parameters:
+ *   None
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+void up_flush_console(void)
+{
+#ifdef CONFIG_UART4_SERIAL_CONSOLE
+	uint16_t nbyte;
+	irqstate_t flags = enter_critical_section();
+
+	/* To avoid duplicated calling up_flush_console(). */
+	if (g_log_flush_running) {
+		leave_critical_section(flags);
+		return;
+	}
+	g_log_flush_running = true;
+
+	do {
+		while (!LOGUART_Ready());
+		nbyte = uart_xmitchars(&CONSOLE_DEV);
+	} while (nbyte);
+
+	g_log_flush_running = false;
+
+	leave_critical_section(flags);
+#endif
+}
+
 #else							/* USE_SERIALDRIVER */
 /****************************************************************************
  * Name: up_putc
diff --git a/os/arch/arm/src/armv7-a/arm_assert.c b/os/arch/arm/src/armv7-a/arm_assert.c
index f41582599c..0247bdcb56 100644
--- a/os/arch/arm/src/armv7-a/arm_assert.c
+++ b/os/arch/arm/src/armv7-a/arm_assert.c
@@ -549,6 +549,21 @@ static inline void print_assert_detail(const uint8_t *filename, int lineno, stru
 
 }
 
+/****************************************************************************
+ * Name: flush_console
+ ****************************************************************************/
+
+static inline void flush_console(void)
+{
+	if (!IS_SECURE_STATE()) {
+		lldbg_noarg("\n===========================================================\n");
+		lldbg_noarg("Flush console log\n");
+		lldbg_noarg("===========================================================\n\n");
+		up_flush_console();
+		lldbg_noarg("\n");
+	}
+}
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -612,6 +627,8 @@ void up_assert(const uint8_t *filename, int lineno)
 	/* Heap corruption check */
 	check_heap_corrupt(fault_tcb);
 
+	flush_console();
+
 	/* Closing log line */
 	lldbg_noarg("##########################################################################################################################################\n");
 
diff --git a/os/arch/arm/src/imx6/imx_serial.c b/os/arch/arm/src/imx6/imx_serial.c
index 3812dd2561..4715092fae 100644
--- a/os/arch/arm/src/imx6/imx_serial.c
+++ b/os/arch/arm/src/imx6/imx_serial.c
@@ -687,7 +687,7 @@ static int imx_interrupt(int irq, void *context, void *arg)
       if (usr1 & UART_USR1_TRDY &&
           (imx_serialin(priv, UART_UCR1_OFFSET) & UART_UCR1_TXEMPTYEN) != 0)
         {
-          uart_xmitchars(dev);
+          (void)uart_xmitchars(dev);
         }
 
       /* Keep track of how many times we do this in case there
diff --git a/os/arch/arm/src/s5j/s5j_serial.c b/os/arch/arm/src/s5j/s5j_serial.c
index 3ffc53b08a..82a60c6e49 100644
--- a/os/arch/arm/src/s5j/s5j_serial.c
+++ b/os/arch/arm/src/s5j/s5j_serial.c
@@ -281,7 +281,7 @@ static int up_interrupt(int irq, void *context, void *arg)
 	uint32_t uintp = uart_getreg32(dev->priv, S5J_UART_UINTP_OFFSET);
 
 	if (uintp & UART_UINTP_TXD) {
-		uart_xmitchars(dev);
+		(void)uart_xmitchars(dev);
 	}
 
 	if (uintp & UART_UINTP_RXD) {
diff --git a/os/arch/arm/src/stm32/stm32_serial.c b/os/arch/arm/src/stm32/stm32_serial.c
index e76bf8a150..d94bf05a5e 100644
--- a/os/arch/arm/src/stm32/stm32_serial.c
+++ b/os/arch/arm/src/stm32/stm32_serial.c
@@ -1761,7 +1761,7 @@ static int up_interrupt_common(struct up_dev_s *priv)
 		if ((priv->sr & USART_SR_TXE) != 0 && (priv->ie & USART_CR1_TXEIE) != 0) {
 			/* Transmit data register empty ... process outgoing bytes */
 
-			uart_xmitchars(&priv->dev);
+			(void)uart_xmitchars(&priv->dev);
 			handled = true;
 		}
 	}
@@ -2260,7 +2260,7 @@ static void up_txint(struct uart_dev_s *dev, bool enable)
 		 * interrupts disabled (note this may recurse).
 		 */
 
-		uart_xmitchars(dev);
+		(void)uart_xmitchars(dev);
 #endif
 	} else {
 		/* Disable the TX interrupt */
diff --git a/os/arch/arm/src/stm32l4/stm32l4_serial.c b/os/arch/arm/src/stm32l4/stm32l4_serial.c
index 5135bc5ac6..a46e4d0c43 100644
--- a/os/arch/arm/src/stm32l4/stm32l4_serial.c
+++ b/os/arch/arm/src/stm32l4/stm32l4_serial.c
@@ -1733,7 +1733,7 @@ static int up_interrupt(int irq, FAR void *context, FAR void *arg)
         {
           /* Transmit data register empty ... process outgoing bytes */
 
-          uart_xmitchars(&priv->dev);
+          (void)uart_xmitchars(&priv->dev);
           handled = true;
         }
     }
@@ -2581,7 +2581,7 @@ static void stm32l4serial_txint(FAR struct uart_dev_s *dev, bool enable)
        * interrupts disabled (note this may recurse).
        */
 
-      uart_xmitchars(dev);
+      (void)uart_xmitchars(dev);
 #endif
     }
   else
diff --git a/os/arch/arm/src/tiva/tiva_serial.c b/os/arch/arm/src/tiva/tiva_serial.c
index 71ebca2447..c7519098ce 100644
--- a/os/arch/arm/src/tiva/tiva_serial.c
+++ b/os/arch/arm/src/tiva/tiva_serial.c
@@ -998,7 +998,7 @@ static int up_interrupt(int irq, void *context, FAR void *arg)
 		if ((mis & UART_MIS_TXMIS) != 0) {
 			/* Tx FIFO not full ... process outgoing bytes */
 
-			uart_xmitchars(dev);
+			(void)uart_xmitchars(dev);
 			handled = true;
 		}
 	}
@@ -1147,7 +1147,7 @@ static void up_txint(struct uart_dev_s *dev, bool enable)
 		 * the TX interrupt.
 		 */
 
-		uart_xmitchars(dev);
+		(void)uart_xmitchars(dev);
 #endif
 	} else {
 		/* Disable the TX interrupt */
diff --git a/os/arch/xtensa/src/esp32/esp32_serial.c b/os/arch/xtensa/src/esp32/esp32_serial.c
index ee90222edb..ee4cf83674 100644
--- a/os/arch/xtensa/src/esp32/esp32_serial.c
+++ b/os/arch/xtensa/src/esp32/esp32_serial.c
@@ -758,7 +758,7 @@ static int esp32_interrupt(int cpuint, void *context, FAR void *arg)
 			if (nfifo < 0x7f) {
 				/* The TXFIFO is not full ... process outgoing bytes */
 
-				uart_xmitchars(dev);
+				(void)uart_xmitchars(dev);
 				handled = true;
 			}
 		}
@@ -1062,7 +1062,7 @@ static void esp32_txint(struct uart_dev_s *dev, bool enable)
 		 * interrupts disabled (note this may recurse).
 		 */
 
-		uart_xmitchars(dev);
+		(void)uart_xmitchars(dev);
 #endif
 	} else {
 		/* Disable the TX interrupt */
diff --git a/os/drivers/serial/serialirq.c b/os/drivers/serial/serialirq.c
index 7189728d5e..fe006482e9 100644
--- a/os/drivers/serial/serialirq.c
+++ b/os/drivers/serial/serialirq.c
@@ -100,7 +100,7 @@
  *
  ************************************************************************************/
 
-void uart_xmitchars(FAR uart_dev_t *dev)
+uint16_t uart_xmitchars(FAR uart_dev_t *dev)
 {
 	uint16_t nbytes = 0;
 
@@ -146,6 +146,8 @@ void uart_xmitchars(FAR uart_dev_t *dev)
 #ifdef CONFIG_SMP
 	leave_critical_section(flags);
 #endif
+
+	return nbytes;
 }
 
 /************************************************************************************
diff --git a/os/drivers/serial/uart_16550.c b/os/drivers/serial/uart_16550.c
index ed177fc622..37ebb316fe 100644
--- a/os/drivers/serial/uart_16550.c
+++ b/os/drivers/serial/uart_16550.c
@@ -787,7 +787,7 @@ static int u16550_interrupt(int irq, void *context, void *arg)
 		/* Handle outgoing, transmit bytes */
 
 		case UART_IIR_INTID_THRE: {
-			uart_xmitchars(dev);
+			(void)uart_xmitchars(dev);
 			break;
 		}
 
@@ -967,7 +967,7 @@ static void u16550_txint(struct uart_dev_s *dev, bool enable)
 		 * interrupts disabled (note this may recurse).
 		 */
 
-		uart_xmitchars(dev);
+		(void)uart_xmitchars(dev);
 	} else {
 		priv->ier &= ~UART_IER_ETBEI;
 		u16550_serialout(priv, UART_IER_OFFSET, priv->ier);
diff --git a/os/include/tinyara/arch.h b/os/include/tinyara/arch.h
index ded6e5d630..1cf2cf001f 100644
--- a/os/include/tinyara/arch.h
+++ b/os/include/tinyara/arch.h
@@ -2530,6 +2530,16 @@ int up_getc(void);
 
 void up_puts(FAR const char *str);
 
+/****************************************************************************
+ * Name: up_flush_console
+ *
+ * Description:
+ *    This function is used to ensure that all characters in the UART buffer
+ *    are transmitted.
+ *
+ ****************************************************************************/
+void up_flush_console(void);
+
 #ifdef CONFIG_WATCHDOG_FOR_IRQ
 /****************************************************************************
  * Name: up_wdog_init
diff --git a/os/include/tinyara/serial/serial.h b/os/include/tinyara/serial/serial.h
index 0c47335353..a2025bfc72 100644
--- a/os/include/tinyara/serial/serial.h
+++ b/os/include/tinyara/serial/serial.h
@@ -348,7 +348,7 @@ int uart_register(FAR const char *path, FAR uart_dev_t *dev);
  *
  ************************************************************************************/
 
-void uart_xmitchars(FAR uart_dev_t *dev);
+uint16_t uart_xmitchars(FAR uart_dev_t *dev);
 
 /************************************************************************************
  * Name: uart_receivechars