diff --git a/src/platform/portduino/USBHal.h b/src/platform/portduino/USBHal.h
index 9a4e7f78a..2b0302ced 100644
--- a/src/platform/portduino/USBHal.h
+++ b/src/platform/portduino/USBHal.h
@@ -6,6 +6,7 @@
 #include <RadioLib.h>
 #include <csignal>
 #include <libpinedio-usb.h>
+#include <unistd.h>
 
 // include the library for Raspberry GPIO pins