diff --git a/sys/dev/usb/usbdi.c b/sys/dev/usb/usbdi.c
index 775d9f9..05bccf8 100644
--- a/sys/dev/usb/usbdi.c
+++ b/sys/dev/usb/usbdi.c
@@ -383,7 +383,8 @@ usbd_start_transfer(void *arg, bus_dma_s
 			 * packet.
 			 */
 			bus_dmamap_sync(tag, dmap->map, BUS_DMASYNC_PREWRITE);
-		}
+		} else
+			bus_dmamap_sync(tag, dmap->map, BUS_DMASYNC_PREREAD);
 	}
 	err = pipe->methods->transfer(xfer);
 	if (err != USBD_IN_PROGRESS && err) {