diff --git a/targets/TARGET_STM/TARGET_STM32WL/system_clock.c b/targets/TARGET_STM/TARGET_STM32WL/system_clock.c
index 70d39202503..2ba82bf9856 100644
--- a/targets/TARGET_STM/TARGET_STM32WL/system_clock.c
+++ b/targets/TARGET_STM/TARGET_STM32WL/system_clock.c
@@ -46,6 +46,15 @@ MBED_WEAK void SetSysClock(void)
     */
     __HAL_RCC_PWR_CLK_ENABLE();
     __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
+
+#if MBED_CONF_TARGET_LSE_AVAILABLE
+    // Enable LSE Oscillator to automatically calibrate the MSI clock
+    RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSE;
+    RCC_OscInitStruct.PLL.PLLState   = RCC_PLL_NONE; // No PLL update
+    RCC_OscInitStruct.LSEState       = RCC_LSE_ON;   // External 32.768 kHz clock on OSC32_IN/OSC32_OUT
+    MBED_ASSERT(HAL_RCC_OscConfig(&RCC_OscInitStruct) == HAL_OK);
+#endif
+
     /** Initializes the CPU, AHB and APB busses clocks
     */
     RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_MSI;
@@ -54,6 +63,11 @@ MBED_WEAK void SetSysClock(void)
     RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_11;
     RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
     MBED_ASSERT(HAL_RCC_OscConfig(&RCC_OscInitStruct) == HAL_OK);
+    
+#if MBED_CONF_TARGET_LSE_AVAILABLE
+    HAL_RCCEx_EnableMSIPLLMode();
+#endif
+    
     /** Configure the SYSCLKSource, HCLK, PCLK1 and PCLK2 clocks dividers
     */
     RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK3 | RCC_CLOCKTYPE_HCLK
@@ -66,4 +80,6 @@ MBED_WEAK void SetSysClock(void)
     RCC_ClkInitStruct.AHBCLK3Divider = RCC_SYSCLK_DIV1;
     MBED_ASSERT(HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) == HAL_OK);
     /* Peripheral clock enable */
-}
+
+    // HAL_RCC_MCOConfig(RCC_MCO1, RCC_MCO1SOURCE_SYSCLK, RCC_MCODIV_1);
+}
\ No newline at end of file
diff --git a/targets/TARGET_STM/serial_api.c b/targets/TARGET_STM/serial_api.c
index 9875c6ed5e0..35a15d815cc 100644
--- a/targets/TARGET_STM/serial_api.c
+++ b/targets/TARGET_STM/serial_api.c
@@ -628,6 +628,11 @@ HAL_StatusTypeDef init_uart(serial_t *obj)
     huart->TxXferSize        = 0;
     huart->RxXferCount       = 0;
     huart->RxXferSize        = 0;
+#if defined(UART_AUTO_BAUD_RATE)
+    huart->AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_AUTOBAUDRATE_INIT;
+    huart->AdvancedInit.AutoBaudRateEnable = UART_ADVFEATURE_AUTOBAUDRATE_ENABLE;
+    huart->AdvancedInit.AutoBaudRateMode = UART_ADVFEATURE_AUTOBAUDRATE_ONSTARTBIT;
+#endif
 #if defined(UART_ONE_BIT_SAMPLE_DISABLE) // F0/F3/F7/G0/H7/L0/L4/L5/WB
     huart->Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
 #endif
@@ -892,4 +897,4 @@ int serial_is_tx_ongoing(void)
     return 0;
 }
 
-#endif /* DEVICE_SERIAL */
+#endif /* DEVICE_SERIAL */
\ No newline at end of file