diff --git a/Tools/serial/rc.serial_port.jinja b/Tools/serial/rc.serial_port.jinja
index 0877321761..94e092660e 100644
--- a/Tools/serial/rc.serial_port.jinja
+++ b/Tools/serial/rc.serial_port.jinja
@@ -5,7 +5,7 @@
 set SERIAL_DEV none
 {% for serial_device in serial_devices -%}
 if param compare "$PRT" {{ serial_device.index }}; then
-	if [ "x$PRT_{{ serial_device.tag }}_" = "x" ]; then
+	if [ "$PRT_{{ serial_device.tag }}_" = "" ]; then
 		set SERIAL_DEV {{ serial_device.device }}
 		set BAUD_PARAM SER_{{ serial_device.tag }}_BAUD
 		set PRT_{{ serial_device.tag }}_ 1