diff --git a/unmodified_drivers/linux-2.6/usbfront/Kbuild b/unmodified_drivers/linux-2.6/usbfront/Kbuild
index f44deaaec5..321a35a122 100644
--- a/unmodified_drivers/linux-2.6/usbfront/Kbuild
+++ b/unmodified_drivers/linux-2.6/usbfront/Kbuild
@@ -1,5 +1,7 @@
 include $(M)/overrides.mk
 
-obj-m += xen-usb.o
+obj-m += $(if $(shell grep '^\#include "\.\./\.\./' $(obj)/usbfront.h), \
+	      $(warning usbfront cannot be built), \
+	      xen-usb.o)
 
 xen-usb-objs := usbfront-hcd.o xenbus.o