Tried with kernel 5.14.0-3.g501d1f1-default #1 SMP Fri Sep 3 04:30:01 UTC 2021 (501d1f1) I cannot reproduce the bug anymore. Also those "hci .. tx timeout" messages when I turn off Bluetooth seems like disappeared. I guess it has been fixed then. P.S File transfer speed is horrible (27kb/sec) but that's separate topic Thank for assistance!