No adapters available for bluetooth Kubuntu

Note: This issue arose as a result of a recent update to the mediatek drivers. If you’re having a similar issue with Mediatek devices, the answer(s) below may be of assistance.

I am using kubuntu 21.10. My Wi-Fi is working fine. But I am not able to use Bluetooth.
I am using dual boot (Linux + Window). I can use Bluetooth in window. Please see my screenshot of Kubuntu.

Note : I have already disabled my secured boot from BIOS options.

Edit 1 :

1. Output of sudo lshw is given in my codepen link.
2. Output of sudo dmesg is given in my codepen link.
3. Output of sudo hcitool dev => Devices:
   (Hence output of sudo hcitool dev is empty).
4. Output of journalctl -xb | grep blue is given below –

░░ Subject: A start job for unit bluetooth.service has begun execution
░░ A start job for unit bluetooth.service has begun execution.
Jan 05 21:54:27 abhishek-kamal-TUF bluetoothd[667]: Bluetooth daemon 5.60
░░ Subject: A start job for unit bluetooth.service has finished successfully
░░ A start job for unit bluetooth.service has finished successfully.
░░ Subject: A start job for unit bluetooth.target has finished successfully
░░ A start job for unit bluetooth.target has finished successfully.
Jan 05 21:54:27 abhishek-kamal-TUF bluetoothd[667]: Starting SDP server
Jan 05 21:54:27 abhishek-kamal-TUF bluetoothd[667]: Bluetooth management interface 1.20 initialized
Jan 05 21:54:27 abhishek-kamal-TUF NetworkManager[670]: <info>  [1641399867.8900] Loaded device plugin: NMBluezManager (/usr/lib/x86_64-linux-gnu/NetworkManager/1.32.12/libnm-device-plugin-bluetooth.so)
Jan 05 21:54:29 abhishek-kamal-TUF systemd-xdg-autostart-generator[1070]: Exec binary 'blueman-applet' does not exist: No such file or directory
Jan 05 21:54:29 abhishek-kamal-TUF systemd-xdg-autostart-generator[1070]: Not generating service for XDG autostart app-blueman@autostart.service, error parsing Exec= line: No such file or directory
Jan 05 21:54:44 abhishek-kamal-TUF systemd-xdg-autostart-generator[1171]: Exec binary 'blueman-applet' does not exist: No such file or directory
Jan 05 21:54:44 abhishek-kamal-TUF systemd-xdg-autostart-generator[1171]: Not generating service for XDG autostart app-blueman@autostart.service, error parsing Exec= line: No such file or directory
Jan 05 21:54:45 abhishek-kamal-TUF systemd-xdg-autostart-generator[1307]: Exec binary 'blueman-applet' does not exist: No such file or directory
Jan 05 21:54:45 abhishek-kamal-TUF systemd-xdg-autostart-generator[1307]: Not generating service for XDG autostart app-blueman@autostart.service, error parsing Exec= line: No such file or directory
Jan 05 21:54:46 abhishek-kamal-TUF dbus-daemon[1178]: [session uid=1000 pid=1178] Activating via systemd: service name='org.bluez.obex' unit='dbus-org.bluez.obex.service' requested by ':1.31' (uid=1000 pid=1405 comm="/usr/bin/kded5 " label="unconfined")
Jan 05 21:54:46 abhishek-kamal-TUF dbus-daemon[1178]: [session uid=1000 pid=1178] Successfully activated service 'org.bluez.obex'

5. Output of sudo lsusb is given below –

Bus 002 Device 002: ID 0781:558a SanDisk Corp. Ultra
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 322e:202c Sonix Technology Co., Ltd. USB2.0 HD UVC WebCam
Bus 001 Device 002: ID 0461:4d81 Primax Electronics, Ltd Dell N889 Optical Mouse
Bus 001 Device 004: ID 13d3:3563 IMC Networks Wireless_Device
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

>Solution :

First, try some general fixes.

1. Try running some troubleshooting commands:

   sudo apt install --reinstall linux-firmware   # reinstall the firmware package with all the latest drivers 
   sudo apt update       # update the repository list
   sudo apt upgrade     # upgrade the list of packages 
   sudo apt install --reinstall linux-firmware
   sudo update-grub      # update grub boot loader 
   sudo apt clean            # remove obsolete packages 
   sudo apt -f install        # try fixing any error in the package manager 
   sudo apt autoremove     # remove no longer needed packages 
   sudo update-grub           # update the boot-loader again! 
   

2. Reboot to confirm:

   reboot
   

If the above didn’t fix your problem, try installing the required package using this PPA.

1. Add the PPA and install the mainline package:

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

2. Load the desired module:

   mainline-gtk
   

Install the latest stable kernel which supports your device.

1. Install the bash script which automatically checks and install the latest kernel:

   wget https://raw.githubusercontent.com/pimlie/ubuntu-mainline-kernel.sh/master/ubuntu-mainline-kernel.sh
   sudo install ubuntu-mainline-kernel.sh /usr/local/bin/
   

2. Run the bash script:

   ubuntu-mainline-kernel.sh -c     ### '-c' option is to check for the latest kernel
   

3. Install the latest stable kernel:

   ubuntu-mainline-kernel.sh -i
   

4. Type Y to accept the installation.

After following the above steps, save the changes using the following steps:

1. Reboot to boot into the latest kernel:

   sudo reboot      
   

2. Now reinstall the Linux firmware package:

   sudo apt install --reinstall linux-firmware
   

Reference: https://miloserdov.org/?p=6899