Hello Nobuhiro, > Could you confirm that the combination of the latest firmware and the > 5.10 kernel solves this problem? Unfortunately, I can't. Freshly updated Bullseye: * linux-image-amd64: 5.10.46-2 * firmware-misc-nonfree: 20210315-2 * bluez-firmware: 1.2-4 Is there any additional information that might be helpful? -- With regards, A