Index: uspace/lib/usb/include/usb/usb.h
===================================================================
--- uspace/lib/usb/include/usb/usb.h	(revision 3dd80f8125dbca151590cbed383c0fad189d40fd)
+++ uspace/lib/usb/include/usb/usb.h	(revision 92a7b2960054bcf03d5c72c214ace89ae53f4d2b)
@@ -152,14 +152,4 @@
 }
 
-static inline bool usb_transfer_type_is_valid(usb_transfer_type_t type)
-{
-	return (type >= 0) && (type < USB_TRANSFER_COUNT);
-}
-
-static inline bool usb_direction_is_valid(usb_direction_t dir)
-{
-	return (dir >= 0) && (dir < USB_DIRECTION_COUNT);
-}
-
 /** USB packet identifier. */
 typedef enum {
Index: uspace/lib/usbhost/src/bus.c
===================================================================
--- uspace/lib/usbhost/src/bus.c	(revision 3dd80f8125dbca151590cbed383c0fad189d40fd)
+++ uspace/lib/usbhost/src/bus.c	(revision 92a7b2960054bcf03d5c72c214ace89ae53f4d2b)
@@ -582,5 +582,4 @@
 	 */
 	assert(usb_target_is_valid(&target));
-	assert(usb_direction_is_valid(direction));
 	assert(direction != USB_DIRECTION_BOTH);
 	assert(size == 0 || data != NULL);