Bluetooth USB dongle 5.0 0a12:0001 doesn't work on Ubuntu 20.04

WIRELESS USB DONGLE - BLUETOOTH USB DONGLE - MINI 5.0 - VERSION 5.48 - 0a12:0001

So lately I bought a Bluetooth USB dongle - model no: MLT-5.0-MiNi

I'm using Ubuntu 20.04.1 LTS.

1. After I connected the adapter into USB port, I checked the port typing in terminal lsusb and I got the following:

Bus 002 Device 003: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)

2. hciconfig -a gave the following:

hci0:   Type: Primary  Bus: USB
        BD Address: 00:1A:7D:DA:71:11  ACL MTU: 679:9  SCO MTU: 48:16
        DOWN
        RX bytes:574 acl:0 sco:0 events:30 errors:0
        TX bytes:368 acl:0 sco:0 commands:30 errors:0
        Features: 0xff 0xff 0x87 0xfa 0xdb 0xbf 0x7b 0x83
        Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3 
        Link policy: RSWITCH HOLD SNIFF PARK 
        Link mode: SLAVE ACCEPT

3. hcitool dev:

Devices:

So it seemed that my PC didn't have the driver installed.

4. bluetoothctl --version:

bluetoothctl: 5.53

5. rfkill:

ID TYPE      DEVICE      SOFT      HARD
0  bluetooth hci0   unblocked unblocked

6. And finally btmon:

Bluetooth monitor ver 5.53
Failed to bind channel: Operation not permitted

I found this YouTube video to solve the problem.

1. First of all, I had to install the app "Ubuntu Mainline Kernel Installer" to update until the lastest kernel version, so I typed:

sudo add-apt-repository ppa:cappelikan/ppa
sudo apt-get update
sudo apt-get install mainline

2. Then, before updating to the last kernel version, I had to check what the running kernel version is:

User@PC:~$ uname -r

5.4.0-48-generic

User@PC:~$ uname -sr

Linux 5.4.0-48-generic

3. Later I went to the website of KERNEL and checked what the last Kernel version that's stable is, for example: 5.8.13

After all, I opened the app Ubuntu Mainline Kernel Installer and clicked the last kernel version that is stable, for example: 5.8.13. Finally clicked the button Install.

4. After the installation and reboot, I checked again:

User@PC:~$ uname -r

5.8.13-050813-generic

User@PC:~$ uname -sr

Linux 5.8.13-050813-generic

I saw that it was successful, and the bluetooth USB DONGLE 5.0 is working.

BUT THERE IS ONE PROBLEM TO CONNECT AFTER PAIRING: After pairing Ubuntu with my speaker 5.0, it cannot connect, then after pairing Ubuntu with my smartphone LG, I couldn't send any pictures to smartphone from Ubuntu nor vice versa.

1. I typed systemctl status bluetooth and entered.

● bluetooth.service - Bluetooth service
     Loaded: loaded (/lib/systemd/system/bluetooth.service; enabled; vendor preset: enabled)
     Active: active (running) since Sat 2020-10-03 19:02:12 -05; 10min ago
       Docs: man:bluetoothd(8)
   Main PID: 2173 (bluetoothd)
     Status: "Running"
      Tasks: 1 (limit: 4649)
     Memory: 2.2M
     CGroup: /system.slice/bluetooth.service
             └─2173 /usr/lib/bluetooth/bluetoothd

oct 03 19:02:11 PC systemd[1]: Starting Bluetooth service...
oct 03 19:02:12 PC bluetoothd[2173]: Bluetooth daemon 5.53
oct 03 19:02:12 PC systemd[1]: Started Bluetooth service.
oct 03 19:02:12 PC bluetoothd[2173]: Starting SDP server
oct 03 19:02:12 PC bluetoothd[2173]: Bluetooth management interface 1.17 initialized
oct 03 19:02:13 PC bluetoothd[2173]: Failed to set mode: Blocked through rfkill (0x12)
oct 03 19:02:14 PC bluetoothd[2173]: Endpoint registered: sender=:1.75 path=/MediaEndpoint/A2DPSink/sbc
oct 03 19:02:14 PC bluetoothd[2173]: Endpoint registered: sender=:1.75 path=/MediaEndpoint/A2DPSource/sbc
oct 03 19:02:14 PC bluetoothd[2173]: Failed to set mode: Blocked through rfkill (0x12)

I see that there is a problem:

bluetoothd[2173]: Failed to set mode: Blocked through rfkill (0x12)

2. rfkill list:

1: hci0: Bluetooth
    Soft blocked: no
    Hard blocked: no

3. hciconfig -a:

hci0:   Type: Primary  Bus: USB
    BD Address: 00:1A:7D:DA:71:11  ACL MTU: 679:9  SCO MTU: 48:16
    UP RUNNING PSCAN ISCAN 
    RX bytes:1174 acl:0 sco:0 events:65 errors:0
    TX bytes:1046 acl:0 sco:0 commands:65 errors:0
    Features: 0xff 0xff 0x87 0xfa 0xdb 0xbf 0x7b 0x83
    Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3 
    Link policy: RSWITCH HOLD SNIFF PARK 
    Link mode: SLAVE ACCEPT 
    Name: 'Daniel-MS-7529'
    Class: 0x1c0104
    Service Classes: Rendering, Capturing, Object Transfer
    Device Class: Computer, Desktop workstation
    HCI Version: 5.0 (0x9)  Revision: 0x810
    LMP Version: 5.0 (0x9)  Subversion: 0x2312
    Manufacturer: Cambridge Silicon Radio (10)

I see that everything is OK.

4. btmon:

Bluetooth monitor ver 5.53
Failed to bind channel: Operation not permitted

5. sudo dmesg | grep -i bluetooth:

[  132.146271] Bluetooth: Core ver 2.22
[  132.146302] Bluetooth: HCI device and connection manager initialized
[  132.146308] Bluetooth: HCI socket layer initialized
[  132.146310] Bluetooth: L2CAP socket layer initialized
[  132.146314] Bluetooth: SCO socket layer initialized
[  132.515401] Bluetooth: hci0: CSR: Unbranded CSR clone detected; adding workarounds...
[  133.859424] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[  133.859426] Bluetooth: BNEP filters: protocol multicast
[  133.859431] Bluetooth: BNEP socket layer initialized
[  135.263551] Bluetooth: RFCOMM TTY layer initialized
[  135.263561] Bluetooth: RFCOMM socket layer initialized
[  135.263570] Bluetooth: RFCOMM ver 1.11
[ 1017.955624] Bluetooth: hci0: inquiry failed: status 0x0c
[ 1023.331631] Bluetooth: hci0: inquiry failed: status 0x0c
[ 3305.392256] Bluetooth: hci0: CSR: Unbranded CSR clone detected; adding workarounds...

There is one more problem:

Bluetooth: hci0: inquiry failed: status 0x0c

6. Another time, I typed on the terminal hcidump -X and entered and then I went to the setting of Bluetooth to try to pair and connect the speaker and I got the following results on the terminal:

HCI sniffer - Bluetooth packet analyzer ver 5.53
device: hci0 snap_len: 1500 filter: 0xffffffffffffffff

[several lines related to HCI Event]

> HCI Event: Command Status (0x0f) plen 4
    Inquiry (0x01|0x0001) status 0x00 ncmd 1
> HCI Event: Extended Inquiry Result (0x2f) plen 255
    bdaddr 88:D0:39:7C:24:61 mode 1 clkoffset 0x2744 class 0x240404 rssi -25
    Complete local name: 'Soundcore Flare+'
    Unknown type 0xff with 9 bytes data
> HCI Event: Extended Inquiry Result (0x2f) plen 255
    bdaddr 24:FC:E5:6E:53:5B mode 1 clkoffset 0x18bd class 0x08043c rssi -71
> HCI Event: Extended Inquiry Result (0x2f) plen 255
    bdaddr 24:FC:E5:6E:53:5B mode 1 clkoffset 0x18bd class 0x08043c rssi -98
> HCI Event: Inquiry Complete (0x01) plen 1
    status 0x00
> HCI Event: Command Complete (0x0e) plen 4
    LE Set Random Address (0x08|0x0005) ncmd 1
    status 0x00
> HCI Event: Command Complete (0x0e) plen 4
    LE Set Scan Parameters (0x08|0x000b) ncmd 1
    status 0x00
> HCI Event: Command Complete (0x0e) plen 4
    LE Set Scan Enable (0x08|0x000c) ncmd 1
    status 0x00
> HCI Event: Command Status (0x0f) plen 4
    Disconnect (0x01|0x0006) status 0x00 ncmd 1
> HCI Event: Command Complete (0x0e) plen 4
    LE Set Scan Enable (0x08|0x000c) ncmd 1
    status 0x00
> HCI Event: Command Status (0x0f) plen 4
    Inquiry (0x01|0x0001) status 0x00 ncmd 1
> HCI Event: Disconn Complete (0x05) plen 4
    status 0x00 handle 128 reason 0x16
    Reason: Connection Terminated by Local Host
> HCI Event: Extended Inquiry Result (0x2f) plen 255
    bdaddr 88:D0:39:7C:24:61 mode 1 clkoffset 0x2745 class 0x240404 rssi -25
    Complete local name: 'Soundcore Flare+'
    Unknown type 0xff with 9 bytes data
> HCI Event: Inquiry Complete (0x01) plen 1
    status 0x00
> HCI Event: Command Complete (0x0e) plen 4
    LE Set Random Address (0x08|0x0005) ncmd 1
    status 0x00
> HCI Event: Command Complete (0x0e) plen 4
    LE Set Scan Parameters (0x08|0x000b) ncmd 1
    status 0x00
> HCI Event: Command Complete (0x0e) plen 4
    LE Set Scan Enable (0x08|0x000c) ncmd 1
    status 0x00
> HCI Event: Command Complete (0x0e) plen 4
    LE Set Scan Enable (0x08|0x000c) ncmd 1
    status 0x00
> HCI Event: Command Status (0x0f) plen 4
    Inquiry (0x01|0x0001) status 0x00 ncmd 1
> HCI Event: Extended Inquiry Result (0x2f) plen 255
    bdaddr 88:D0:39:7C:24:61 mode 1 clkoffset 0x2745 class 0x240404 rssi -27
    Complete local name: 'Soundcore Flare+'
    Unknown type 0xff with 9 bytes data
> HCI Event: Extended Inquiry Result (0x2f) plen 255
    bdaddr 88:D0:39:7C:24:61 mode 1 clkoffset 0x2745 class 0x240404 rssi -27
    Complete local name: 'Soundcore Flare+'
    Unknown type 0xff with 9 bytes data
> HCI Event: Extended Inquiry Result (0x2f) plen 255
    bdaddr 88:D0:39:7C:24:61 mode 1 clkoffset 0x2745 class 0x240404 rssi -24
    Complete local name: 'Soundcore Flare+'
    Unknown type 0xff with 9 bytes data
> HCI Event: Extended Inquiry Result (0x2f) plen 255
    bdaddr 88:D0:39:7C:24:61 mode 1 clkoffset 0x2745 class 0x240404 rssi -24
    Complete local name: 'Soundcore Flare+'
    Unknown type 0xff with 9 bytes data
> HCI Event: Extended Inquiry Result (0x2f) plen 255
    bdaddr 88:D0:39:7C:24:61 mode 1 clkoffset 0x2745 class 0x240404 rssi -23
    Complete local name: 'Soundcore Flare+'
    Unknown type 0xff with 9 bytes data
> HCI Event: Extended Inquiry Result (0x2f) plen 255
    bdaddr 88:D0:39:7C:24:61 mode 1 clkoffset 0x2745 class 0x240404 rssi -24
    Complete local name: 'Soundcore Flare+'
    Unknown type 0xff with 9 bytes data
> HCI Event: Extended Inquiry Result (0x2f) plen 255
    bdaddr 88:D0:39:7C:24:61 mode 1 clkoffset 0x2745 class 0x240404 rssi -23
    Complete local name: 'Soundcore Flare+'
    Unknown type 0xff with 9 bytes data
> HCI Event: Extended Inquiry Result (0x2f) plen 255
    bdaddr 88:D0:39:7C:24:61 mode 1 clkoffset 0x2745 class 0x240404 rssi -22
    Complete local name: 'Soundcore Flare+'
    Unknown type 0xff with 9 bytes data

Soundcore Flare+ is the speaker's model. I see there is one another problem:

Unknown type 0xff with 9 bytes data

The Bluetooth USB 5.0 works fine on Windows 10 but on Ubuntu 20.04, it doesn't work. So Ubuntu needs drivers for Bluetooth 5.0.

On 5.8.14 Kernel, Ubuntu really displays devices to pair and connect, but the pairing and connecting don't work.

So, could anyone help me to solve this problem of pairing and connecting with devices from Ubuntu?

I found the problem solved for Linux in this website but I don't know how to compile and patch on Ubuntu 20.04, it can work only for Kernel's version 5.8.