diff --git a/tools/build.py b/tools/build.py
index 636ce047f..0fed44df3 100755
--- a/tools/build.py
+++ b/tools/build.py
@@ -25,7 +25,6 @@ from __future__ import print_function
 import sys
 import os
 import argparse
-import serial
 import subprocess
 import tempfile
 import shutil