Re: Is there a way to force legacy LE pairing for a device

[Jacek Konieczny <jajcus@jajcus.net>]

Hi Luiz,

On 01/11/2021 21:21, Luiz Augusto von Dentz wrote:
> 
> On Mon, Nov 1, 2021 at 10:26 AM Jacek Konieczny <jajcus@jajcus.net> wrote:
>> So it looks like 'Bonding, MITM, Legacy, No Keypresses' used by Android
>> works and 'Bonding, No MITM, SC, No Keypresses, CT2' used by the desktop
>> Linux (bluez 5.62, kernel '5.6.2-050602-lowlatency' from Ubuntu) does
>> not (note: I am still quite ignorant about Bluetooth stuff).
> 
> What android version are we talking about here?

Android 11 on Samsung Galaxy S10 with current software.

>> So my question is: is there any way to force using legacy pairing? Even
>> if that requires bluez or kernel patching (though, I would rather avoid
>> that).
> 
> So Invalid Parameter is normally used when the stack doesn't
> understand something in the request:
> 
> 'x0A Invalid Parameters The Invalid Parameters error code indicates
> that the command length is invalid or that a
> parameter is outside of the specified range.'
> 
>  From the looks of it Android doesn't set SC nor CT2, which were bits
> introduced after 4.0, so perhaps with this version of Android we
> cannot use one of these bits (CT2 most likely).

The problem is not the Android, but the device I am trying to pair with 
(VOX Adio Air GT guitar amplifier). The Bluetooth implementation in the 
device is most probably outdated or/and broken and definitely insecure, 
but I still need to connect to it. Android can do that, I wonder how I 
can do it from a regular Linux machine with recent kernel and Bluez.

Jacek