diff --git a/src/serial.c b/src/serial.c
index 0e317f6..877add6 100644
--- a/src/serial.c
+++ b/src/serial.c
@@ -232,6 +232,7 @@ int serial_open_advanced(serial_t *serial, const char *path, uint32_t baudrate,
     if (tcsetattr(serial->fd, TCSANOW, &termios_settings) < 0) {
         int errsv = errno;
         close(serial->fd);
+        serial->fd = -1;
         return _serial_error(serial, SERIAL_ERROR_CONFIGURE, errsv, "Setting serial port attributes");
     }