diff --git a/sys/dev/uart/uart_dev_ns8250.c b/sys/dev/uart/uart_dev_ns8250.c
--- a/sys/dev/uart/uart_dev_ns8250.c
+++ b/sys/dev/uart/uart_dev_ns8250.c
@@ -359,10 +359,6 @@
 {
 	u_char ier;
 
-	if (bas->rclk == 0)
-		bas->rclk = DEFAULT_RCLK;
-	ns8250_param(bas, baudrate, databits, stopbits, parity);
-
 	/* Disable all interrupt sources. */
 	/*
 	 * We use 0xe0 instead of 0xf0 as the mask because the XScale PXA
@@ -373,6 +369,10 @@
 	uart_setreg(bas, REG_IER, ier);
 	uart_barrier(bas);
 
+	if (bas->rclk == 0)
+		bas->rclk = DEFAULT_RCLK;
+	ns8250_param(bas, baudrate, databits, stopbits, parity);
+
 	/* Disable the FIFO (if present). */
 	uart_setreg(bas, REG_FCR, 0);
 	uart_barrier(bas);