diff --git a/hw/usb.h b/hw/usb.h
index 7e46141..ca06bf8 100644
--- a/hw/usb.h
+++ b/hw/usb.h
@@ -124,6 +124,7 @@
 #define USB_DT_ENDPOINT			0x05
 #define USB_DT_DEVICE_QUALIFIER         0x06
 #define USB_DT_OTHER_SPEED_CONFIG       0x07
+#define USB_DT_INTERFACE_ASSOC          0x0B
 
 #define USB_ENDPOINT_XFER_CONTROL	0
 #define USB_ENDPOINT_XFER_ISOC		1