diff --git a/fw/Core/Src/main.c b/fw/Core/Src/main.c
index 392ce98..9993b8e 100644
--- a/fw/Core/Src/main.c
+++ b/fw/Core/Src/main.c
@@ -231,33 +231,6 @@ int main(void)
   /* Enter the main loop */
   while (1)
   {
-	  /* UART RX is done */
-	  if (lpuart1_rx_done == 1)
-	  {
-	  /* Process the message */
-		  if (lpuart1_rx_message_too_long)
-		  {
-			  /* Do nothing, just delete the buffer and set the flag back to zero*/
-			  lpuart1_rx_message_too_long = 0;
-		  } else
-		  {
-			  /* Process the message:
-			   * message is stored in modbus_buffer[], no copying necessary;
-			   * but we need to make sure that modbus_buffer[] will not be used while
-			   * processing the message: this can be done by disabling RX interrupt */
-			  LL_LPUART_DisableIT_RXNE(LPUART1);
-			  modbus_slave_process_msg(modbus_buffer, lpuart1_rx_message_len);
-			  /* Reset the RX DONE flag */
-			  lpuart1_rx_done = 0;
-			  LL_LPUART_EnableIT_RXNE(LPUART1);
-		  }
-		  /* Reset the RX DONE flag */
-		  lpuart1_rx_done = 0;
-
-
-
-	  }
-
 	  /* It is time for measurement */
 	  if (tim21_elapsed_period == 1)
 	  {
diff --git a/fw/Core/Src/stm32l0xx_it.c b/fw/Core/Src/stm32l0xx_it.c
index 0d36df7..9ee73af 100644
--- a/fw/Core/Src/stm32l0xx_it.c
+++ b/fw/Core/Src/stm32l0xx_it.c
@@ -45,8 +45,6 @@
 /* USER CODE BEGIN PV */
 uint16_t lpuart1_rx_message_index = 0;
 uint16_t lpuart1_rx_message_len = 0;
-uint8_t lpuart1_rx_done = 0;
-uint8_t lpuart1_rx_message_too_long = 0;
 
 uint8_t tim21_elapsed_period = 0;
 /* USER CODE END PV */
@@ -166,19 +164,16 @@ void TIM21_IRQHandler(void)
   */
 void LPUART1_IRQHandler(void)
 {
-  /* USER CODE BEGIN LPUART1_IRQn 0 */
-
-
+	/* USER CODE BEGIN LPUART1_IRQn 0 */
     /* Check RXNE flag value in SR register */
-  if(LL_LPUART_IsActiveFlag_RXNE(LPUART1) && LL_LPUART_IsEnabledIT_RXNE(LPUART1))
-  {
-    /* RXNE flag will be cleared by reading of DR register (done in call) */
-    /* Call function in charge of handling Character reception */
-	  LPUART1_CharReception_Callback();
-  }
-
-  /* USER CODE END LPUART1_IRQn 0 */
-  /* USER CODE BEGIN LPUART1_IRQn 1 */
+	if(LL_LPUART_IsActiveFlag_RXNE(LPUART1) && LL_LPUART_IsEnabledIT_RXNE(LPUART1))
+	{
+		/* RXNE flag will be cleared by reading of DR register (done in call) */
+		/* Call function in charge of handling Character reception */
+		LPUART1_CharReception_Callback();
+	}
+	/* USER CODE END LPUART1_IRQn 0 */
+	/* USER CODE BEGIN LPUART1_IRQn 1 */
 	/* If the IDLE flag is active */
 	if (LL_LPUART_IsActiveFlag_IDLE(LPUART1) && LL_LPUART_IsEnabledIT_IDLE(LPUART1))
 	{
@@ -188,11 +183,18 @@ void LPUART1_IRQHandler(void)
 		/* Reset the buffer index */
 		lpuart1_rx_message_len = lpuart1_rx_message_index;
 		lpuart1_rx_message_index = 0;
-		lpuart1_rx_done = 1;
 		if (lpuart1_rx_message_len > MODBUS_MAX_RTU_FRAME_SIZE)
 		{
-			lpuart1_rx_message_too_long = 1;
+			/* message too long, ignore */
+			return;
 		}
+		/* Process the message:
+		* message is stored in modbus_buffer[], no copying necessary;
+		* but we need to make sure that modbus_buffer[] will not be used while
+		* processing the message: this can be done by disabling RX interrupt */
+		LL_LPUART_DisableIT_RXNE(LPUART1);
+		modbus_slave_process_msg(modbus_buffer, lpuart1_rx_message_len);
+		LL_LPUART_EnableIT_RXNE(LPUART1);
 	}
   /* USER CODE END LPUART1_IRQn 1 */
 }