RUM_BULK_WR
usbd_transfer_start(sc->sc_xfer[RUM_BULK_WR]);
usbd_transfer_start(sc->sc_xfer[RUM_BULK_WR]);
usbd_transfer_start(sc->sc_xfer[RUM_BULK_WR]);
usbd_transfer_start(sc->sc_xfer[RUM_BULK_WR]);
usbd_xfer_set_stall(sc->sc_xfer[RUM_BULK_WR]);
usbd_transfer_drain(sc->sc_xfer[RUM_BULK_WR]);
[RUM_BULK_WR] = {