Tvheadend, ability to add firmware file for a tuner

My best regards. I've successfully connected an Xbox one tuner to an Android smartphone with broken screen to use it as a Tvh server.
Having installed all the necessary dependencies and followed the very well laid down wiki here, I've successfully got all the device details just as expected, this meaning that my setup is fine but I've seen that Termux hasn't the lib/firmware folder (under /data/data/com.termux/files/usr, that's clear) so I don't know how to make tvheadend see the tuner given that, at least by what I know, the only way is putting the relevant fw which can be downloaded here inside that folder.
Done it already elsewhere but not under Android where USB low level access is shielded from the outside, I know.
Maybe I'm trying to achieve something which is just plain impossible but I feel so close (I've set Tvh under Termux up too and it works like a charm but, without getting the tuner to work with it, it has no purpose for me) that it would be a pity should this prove to be the case.
Thanks in advance for your advices. :)

Review the Termux-usb wiki guidance and the Android path /data/data/com.termux/files/usr/lib/firmware, then compare that with how tvheadend loads the named firmware file. Done means establishing whether Termux can expose or install this firmware for the tuner, and documenting the supported path or the platform limitation.