diff --git a/src/machine/serial-none.go b/src/machine/serial-none.go
index 3596769f4..d502812eb 100644
--- a/src/machine/serial-none.go
+++ b/src/machine/serial-none.go
@@ -5,3 +5,6 @@ package machine
 
 // Serial is a null device: writes to it are ignored.
 var Serial = NullSerial{}
+
+func InitSerial() {
+}
diff --git a/src/machine/serial-uart.go b/src/machine/serial-uart.go
index 30575502d..e0525d98d 100644
--- a/src/machine/serial-uart.go
+++ b/src/machine/serial-uart.go
@@ -5,3 +5,7 @@ package machine
 
 // Serial is implemented via the default (usually the first) UART on the chip.
 var Serial = DefaultUART
+
+func InitSerial() {
+	Serial.Configure(UARTConfig{})
+}
diff --git a/src/machine/serial-usb.go b/src/machine/serial-usb.go
index ac484f87a..0bec8e297 100644
--- a/src/machine/serial-usb.go
+++ b/src/machine/serial-usb.go
@@ -5,3 +5,6 @@ package machine
 
 // Serial is implemented via USB (USB-CDC).
 var Serial = USB
+
+func InitSerial() {
+}
diff --git a/src/runtime/runtime_atsamd51.go b/src/runtime/runtime_atsamd51.go
index 48236085b..40237be53 100644
--- a/src/runtime/runtime_atsamd51.go
+++ b/src/runtime/runtime_atsamd51.go
@@ -34,6 +34,7 @@ func init() {
 	//}
 
 	machine.InitUSB()
+	machine.InitSerial()
 }
 
 func putchar(c byte) {