diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
index 01d5ad2479f4..f2224eb0bf6b 100644
--- a/drivers/bluetooth/btmtk.c
+++ b/drivers/bluetooth/btmtk.c
@@ -1557,8 +1557,15 @@ static int btmtk_recv_isopkt(struct hci_dev *hdev, void *buffer, int count)
 	struct btmtk_data *btmtk_data = hci_get_priv(hdev);
 	struct sk_buff *skb;
 	unsigned long flags;
+	unsigned int iso_mtu;
 	int err = 0;
 
+	/* The controller reports the largest Data_Total_Length it will send in
+	 * LE Read Buffer Size [v2]. Fall back to HCI_MAX_ISO_SIZE while that
+	 * command has not completed yet.
+	 */
+	iso_mtu = hdev->iso_mtu ? hdev->iso_mtu : HCI_MAX_ISO_SIZE;
+
 	spin_lock_irqsave(&btmtk_data->isorxlock, flags);
 	skb = btmtk_data->isopkt_skb;
 
@@ -1574,7 +1581,8 @@ static int btmtk_recv_isopkt(struct hci_dev *hdev, void *buffer, int count)
 			if (mem_is_zero(buffer, count))
 				break;
 
-			skb = bt_skb_alloc(HCI_MAX_ISO_SIZE, GFP_ATOMIC);
+			skb = bt_skb_alloc(HCI_ISO_HDR_SIZE + iso_mtu,
+					   GFP_ATOMIC);
 			if (!skb) {
 				err = -ENOMEM;
 				break;
@@ -1608,7 +1616,13 @@ static int btmtk_recv_isopkt(struct hci_dev *hdev, void *buffer, int count)
 				break;
 			}
 
-			if (skb_tailroom(skb) < hci_skb_expect(skb)) {
+			/* Reject a length the controller said it would never
+			 * send. The skb_tailroom() test is kept because a
+			 * fragment started before hdev->iso_mtu was populated
+			 * sits in a smaller skb than iso_mtu now allows.
+			 */
+			if (hci_skb_expect(skb) > iso_mtu ||
+			    skb_tailroom(skb) < hci_skb_expect(skb)) {
 				kfree_skb(skb);
 				skb = NULL;