diff --git a/build/image/generate_initrd.py b/build/image/generate_initrd.py
index aba5ec1..901bc68 100644
--- a/build/image/generate_initrd.py
+++ b/build/image/generate_initrd.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 #
 # Copyright 2018 The Hafnium Authors.
 #