diff --git a/firmware/ice40-riscv/icE1usb/usb_e1.h b/firmware/ice40-riscv/icE1usb/usb_e1.h
index a573b38..06723ea 100644
--- a/firmware/ice40-riscv/icE1usb/usb_e1.h
+++ b/firmware/ice40-riscv/icE1usb/usb_e1.h
@@ -7,5 +7,5 @@
 
 #pragma once
 
-void usb_e1_run(void);
+void usb_e1_run(int port);
 void usb_e1_init(void);