Index: uspace/lib/usbhost/include/usb/host/endpoint.h
===================================================================
--- uspace/lib/usbhost/include/usb/host/endpoint.h	(revision 5cfcc64e92606f3061133bd63ecf20bffd081ac5)
+++ uspace/lib/usbhost/include/usb/host/endpoint.h	(revision 295f658e35808c59ff0e8afaebeea572ff2b4648)
@@ -95,9 +95,9 @@
 /** list_get_instance wrapper.
  * @param item Pointer to link member.
- * @return Pointer to enpoint_t structure.
+ * @return Pointer to endpoint_t structure.
  */
 static inline endpoint_t * endpoint_get_instance(link_t *item)
 {
-	return list_get_instance(item, endpoint_t, link);
+	return item ? list_get_instance(item, endpoint_t, link) : NULL;
 }
 #endif
Index: uspace/lib/usbhost/include/usb/host/usb_device_manager.h
===================================================================
--- uspace/lib/usbhost/include/usb/host/usb_device_manager.h	(revision 5cfcc64e92606f3061133bd63ecf20bffd081ac5)
+++ uspace/lib/usbhost/include/usb/host/usb_device_manager.h	(revision 295f658e35808c59ff0e8afaebeea572ff2b4648)
@@ -59,5 +59,7 @@
 		devman_handle_t handle; /**< Devman handle of the device. */
 	} devices[USB_ADDRESS_COUNT];
+	/** Maximum speed allowed. */
 	usb_speed_t max_speed;
+	/** Protect access to members. */
 	fibril_mutex_t guard;
 	/** The last reserved address */
Index: uspace/lib/usbhost/include/usb/host/usb_transfer_batch.h
===================================================================
--- uspace/lib/usbhost/include/usb/host/usb_transfer_batch.h	(revision 5cfcc64e92606f3061133bd63ecf20bffd081ac5)
+++ uspace/lib/usbhost/include/usb/host/usb_transfer_batch.h	(revision 295f658e35808c59ff0e8afaebeea572ff2b4648)
@@ -65,10 +65,17 @@
 	 */
 	size_t setup_size;
-	/** Actually used portion of the buffer */
-	size_t transfered_size;
-	/** Indicates success/failure of the communication */
-	int error;
 	/** Host controller function, passed to callback function */
 	ddf_fun_t *fun;
+
+	/** Actually used portion of the buffer
+	 * This member is never accessed by functions provided in this header,
+	 * with the exception of usb_transfer_batch_finish. For external use.
+	 */
+	size_t transfered_size;
+	/** Indicates success/failure of the communication
+	 * This member is never accessed by functions provided in this header,
+	 * with the exception of usb_transfer_batch_finish. For external use.
+	 */
+	int error;
 
 	/** Driver specific data */
@@ -109,9 +116,8 @@
     const void* data, size_t size, int error);
 /*----------------------------------------------------------------------------*/
-/** Finish batch using stored error value.
+/** Finish batch using stored error value and transferred size.
  *
  * @param[in] instance Batch structure to use.
  * @param[in] data Data to copy to the output buffer.
- * @param[in] size Size of @p data.
  */
 static inline void usb_transfer_batch_finish(