Index: uspace/drv/nic/virtio-net/virtio-net.c
===================================================================
--- uspace/drv/nic/virtio-net/virtio-net.c	(revision 9319b7d0ca4af622067b3b87f26c170075e3b39b)
+++ uspace/drv/nic/virtio-net/virtio-net.c	(revision 4810acfa30c0ba5b1f5d6a232f7ab983b3c957ea)
@@ -416,5 +416,5 @@
 	 */
 	virtio_virtq_desc_set(vdev, TX_QUEUE_1, descno,
-	    virtio_net->tx_buf_p[descno], TX_BUF_SIZE, 0, 0);
+	    virtio_net->tx_buf_p[descno], sizeof(virtio_net_hdr_t) + size, 0, 0);
 	virtio_virtq_produce_available(vdev, TX_QUEUE_1, descno);
 }