diff --git a/tx.c b/tx.c
index 9a0873da..05671906 100644
--- a/tx.c
+++ b/tx.c
@@ -140,7 +140,7 @@ int mt76_tx_queue_skb(struct mt76_dev *dev, struct mt76_queue *q,
 		buf[n++].len = iter->len;
 	}
 
-	if (q->queued + (n + 1) / 2 >= q->ndesc)
+	if (q->queued + (n + 1) / 2 >= q->ndesc - 1)
 		goto unmap;
 
 	return dev->queue_ops->add_buf(dev, q, buf, n, tx_info, skb, t);