diff --git a/libcpu/arm/stm32/serial.c b/libcpu/arm/stm32/serial.c
index c5dbb0b24..41f8e74a9 100644
--- a/libcpu/arm/stm32/serial.c
+++ b/libcpu/arm/stm32/serial.c
@@ -107,7 +107,7 @@ static rt_err_t rt_serial_init (rt_device_t dev)
 			rt_memset(uart->int_rx->rx_buffer, 0, 
 				sizeof(uart->int_rx->rx_buffer));
 			uart->int_rx->read_index = 0;
-                        uart->int_rx->read_index = 0;
+			uart->int_rx->save_index = 0;
 		}
 		
 		if (dev->flag & RT_DEVICE_FLAG_DMA_RX)