diff --git a/drivers/serial/serial_uniphier.c b/drivers/serial/serial_uniphier.c
index 2ffab004bd793471d5215fbb60e73e16dcd397d7..aaf8657ee14b8f85ef0f3ebc92488840d9505471 100644
--- a/drivers/serial/serial_uniphier.c
+++ b/drivers/serial/serial_uniphier.c
@@ -43,6 +43,10 @@ static int uniphier_serial_setbrg(struct udevice *dev, int baudrate)
 
 	divisor = DIV_ROUND_CLOSEST(priv->uartclk, mode_x_div * baudrate);
 
+	/* flush the trasmitter before changing hw setting */
+	while (!(readl(priv->membase + UNIPHIER_UART_LSR) & UART_LSR_TEMT))
+		;
+
 	writel(divisor, priv->membase + UNIPHIER_UART_DLR);
 
 	return 0;
@@ -132,6 +136,10 @@ static int uniphier_serial_probe(struct udevice *dev)
 
 	priv->uartclk = clk_data->clk_rate;
 
+	/* flush the trasmitter empty before changing hw setting */
+	while (!(readl(priv->membase + UNIPHIER_UART_LSR) & UART_LSR_TEMT))
+		;
+
 	tmp = readl(priv->membase + UNIPHIER_UART_LCR_MCR);
 	tmp &= ~UNIPHIER_UART_LCR_MASK;
 	tmp |= FIELD_PREP(UNIPHIER_UART_LCR_MASK, UART_LCR_WLEN8);