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filofel avatar Ubuntu

Bluetooth not loading anymore on Ubuntu 20.04.6 LTS

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filofel

Bluetooth doesn't work anymore on my HP 8560w.
Systems Settings show "No Bluetooth Found, Plug in a dongle to use Bluetooth".
And yes, the one switch that controls both Wifi and Bluetooth is enabled. And Airplane mode is off, too!
Note that Bluetooth did work in the past on that machine, but since I didn't use BT for some time, I don't know when it broke (nor what update broke it).
And no track of a blutooth error in kern.log or syslog.

I ran and uploaded a probe to linux-hardware.org, and the host section shows that the detected hardware is an "HP, Inc Broadcom 2070 Bluetooth Combo" and that the required driver is btusb:
USB 03f0:231d / e0-01-01 HP,Inc Broadcom 2070 Bluetooth Combo bluetooth btusb detected

Running lsmod:
$ sudo lsmod

Upon boot:
result: No bt* driver module that I can see in the list.

After running
sudo modprobe btusb,
I get
Module Size Used by
btusb 57344 0
btrtl 24576 1 btusb
btbcm 16384 1 btusb
btintel 24576 1 btusb

btbcm is described as "Bluetooth support for Broadcom devices". So btusb has loaded, and its (hardware) dependencies too.
But I still have Systems Settings showing
No Bluetooth Found - Plug in a dongle to use Bluetooth.

I have looked at the various "similar questions" suggested by ask ubuntu, particularly:
Trouble turning on bluetooth in 12.04 but didn't find any suitable (and/or working) clue for 20.04.6.
I also googled around to, and found nothing that would solve it.

  1. Does anyone know why btusb (and dependencies) are not autoloaded anymore at boot in myUbuntu 20.04.6 LTS, or how to find out?

  2. As a side question, I wonder why the system still doesn't see Bluetooth hardware after I manually load the proper driver?...
    $ sudo hcitool scan
    Device is not available: No such device

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filofel avatar Ubuntu
us flag
filofel

My Bluetooth is working again.
I first thought it was a missing firmware file problem after reading this Github page, and specially this paragraph:

This package intends to provide firmware of Broadcom WIDCOMM® Bluetooth devices (including BCM20702, BCM20703, BCM43142 chipsets and other) for Linux kernel.

Specially after noticing that there was apparently no BCM2070x firmware file in my
/lib/firmware/brcm
directory for the 2070-2 Bluetooth combo in my machine, while there were plenty appearing in the files on the Github project file list.
But after I installed the .deb packages from there, Bluetooth still didn't start.
Then as a last (desperate) attempt, I did something someone had suggested in one of the posts I had read while searching, i.e. to reset the BIOS config to factory defaults. I had previously merely checked the BIOS parms, had found nothing suspicious there, and considered there was no apparent reason to reset this BIOS config.
Well, that did fixed it.
And even after I have totally removed the Github .deb firmware package from my machine, Bluetooth still works. So whatever firmware the adapter requires is probably already in the 20.04.6 distro under some funky name. Go figure...

Now that still leaves some good reasons to worry.
The aforementioned Github page says:

Recently several vulnerabilities have been discovered in the Bluetooth stack such as CVE-2018-5383, CVE-2019-9506 (KNOB), CVE-2020-10135 (BIAS) and more. Since Broadcom has stopped active support for its consumer devices, your system may be subject to security risks. You will have to use these devices at your own risk. As a repository maintainer, I cannot provide security fixes.

After checking the CVE reports, this means anyone using the darn drivers should only enable Bluetooth when no suspicious machine is within Bluetooth waves reception range.
Or should disable the 2070 Broadcom combo altogether and buy a recent, reputable Bluetooth dongle.
Or should decide to ignore this, hope for the best and permanently play Bluetooth Russian Roulette.

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