diff --git a/fastboot/engine.cpp b/fastboot/engine.cpp
index bda6ad8..a0e990a 100644
--- a/fastboot/engine.cpp
+++ b/fastboot/engine.cpp
@@ -30,6 +30,7 @@
 #include "fs.h"
 
 #include <errno.h>
+#include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>