diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 49a998804908..c730da87734b 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -3876,7 +3876,11 @@ static int l2cap_parse_conf_rsp(struct l2cap_chan *chan, void *rsp, int len,
 		}
 	}
 
-	if (chan->mode == L2CAP_MODE_BASIC && chan->mode != rfc.mode)
+	/* A connected channel cannot change its mode, as the new mode would
+	 * not be initialized.
+	 */
+	if (chan->mode != rfc.mode &&
+	    (chan->mode == L2CAP_MODE_BASIC || chan->state == BT_CONNECTED))
 		return -ECONNREFUSED;
 
 	chan->mode = rfc.mode;