Public bug reported:
Hardware: ASUS F15-FX506HC. Internal MediaTek MT7921 Wi-Fi/Bluetooth combo;
Wi-Fi via mt7921e (PCIe 14c3:7961), Bluetooth via btusb/btmtk (USB 13d3:3563,
usb 3-14).
Release: Ubuntu 26.04.1 (upgraded from 24.04 on 2026-10-04). Kernel
7.0.0-38-generic. linux-firmware 20260319.git217ca6e4.1ubuntu. BlueZ
5.85-4ubuntu0.3.
Problem:
The Bluetooth USB function disconnects from the bus. Usually it re-enumerates
within a second, but several times it never comes back. Then the kernel logs:
usb 3-14: USB disconnect, device number 5
usb 3-14: device descriptor read/64, error -71
usb 3-14: Device not responding to setup address.
usb 3-14: device not accepting address 10, error -71
usb 3-14: WARN: invalid context state for evaluate context command.
usb usb3-port14: unable to enumerate USB device
After that hci0 and the Bluetooth rfkill entry are gone, `bluetoothctl list` is
empty, and GNOME hides the Bluetooth icon. bluetoothd keeps running. Wi-Fi on
the same chip keeps working. A full power-off is needed to recover Bluetooth.
Most recent occurrence: 2026-10-11 10:35:33, about 20 minutes after
boot, with no Bluetooth audio device connected and no "corrupted SCO
packet" messages before it. On other days it often follows bursts of
"Bluetooth: hci0: corrupted SCO packet" while a headset is in use.
Per-boot history (journalctl, usb 3-14):
Period Ubuntu Kernel BT fw build Boots Disconnects
Unrecoverable Corrupted SCO
23 Sep - 1 Oct 24.04 7.0.0-34 20240219111427 14 1 0
11
1 Oct - 4 Oct 24.04 7.0.0-38 20240219111427 6 5 0
14
4 Oct - 11 Oct 26.04 7.0.0-38 20260224111243 11 29 5
105
The new firmware (build 20260224111243) was first loaded on 2026-10-04 17:10
after linux-firmware was upgraded from 20240318.git3b128b60-0ubuntu3.1 to
20260319.git217ca6e4.1ubuntu. Since then, disconnects are much more frequent
and unrecoverable losses happened on 6, 8, 9 and 11 (twice) October. With the
old firmware the device always recovered. The kernel version is the same before
and after, so a linux-firmware (MediaTek BT_RAM_CODE_MT7961_1_2_hdr.bin)
regression is suspected, possibly together with btusb/btmtk reset handling.
Kernel command line: quiet splash pcie_aspm=off rfkill.default_state=1
asus_wmi.fnlock_default=0
Attached: per-boot-summary.txt, kernel-bt-usb-excerpt.log (11 Oct
10:15-10:37), lsusb.txt, package-versions.txt.
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-7.0.0-38-generic 7.0.0-38.38
ProcVersionSignature: Ubuntu 7.0.0-38.38-generic 7.0.14
Uname: Linux 7.0.0-38-generic x86_64
ApportVersion: 2.34.1-0ubuntu0.1
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: presiyan 4466 F.... wireplumber
/dev/snd/controlC2: presiyan 4466 F.... wireplumber
/dev/snd/controlC1: presiyan 4466 F.... wireplumber
/dev/snd/seq: presiyan 4451 F.... pipewire
CRDA: N/A
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Sun Oct 11 15:00:48 2026
InstallationDate: Installed on 2023-12-27 (1019 days ago)
InstallationMedia: Ubuntu 22.04.3 LTS "Jammy Jellyfish" - Release amd64
(20230807.2)
MachineType: ASUSTeK COMPUTER INC. ASUS TUF Gaming F15 FX506HC_FX506HC
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-7.0.0-38-generic
root=UUID=a5e9d595-c55d-467f-9724-ea5097813566 ro quiet splash pcie_aspm=off
rfkill.default_state=1 asus_wmi.fnlock_default=0
RfKill:
1: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
SourcePackage: linux
UpgradeStatus: Upgraded to resolute on 2026-10-04 (7 days ago)
dmi.bios.date: 06/17/2025
dmi.bios.release: 5.19
dmi.bios.vendor: American Megatrends International, LLC.
dmi.bios.version: FX506HC.316
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: FX506HC
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: 1.0
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK COMPUTER INC.
dmi.chassis.version: 1.0
dmi.ec.firmware.release: 3.10
dmi.modalias:
dmi:bvnAmericanMegatrendsInternational,LLC.:bvrFX506HC.316:bd06/17/2025:br5.19:efr3.10:svnASUSTeKCOMPUTERINC.:pnASUSTUFGamingF15FX506HC_FX506HC:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnFX506HC:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0:sku:pfaASUSTUFGamingF15:
dmi.product.family: ASUS TUF Gaming F15
dmi.product.name: ASUS TUF Gaming F15 FX506HC_FX506HC
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK COMPUTER INC.
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute wayland-session
** Attachment added: "bt-mt7921-evidence.txt"
https://bugs.launchpad.net/bugs/2170483/+attachment/6008149/+files/bt-mt7921-evidence.txt
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https://bugs.launchpad.net/bugs/2170483
Title:
[MT7921 13d3:3563] Bluetooth USB device drops off the bus and cannot
re-enumerate (error -71) since upgrade to 26.04 / linux-firmware
20260319
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