It's not the firmware itself but how it's applied. We've been through this extensively before:
https://forum.elivelinux.org/t/installing-3-8-43-to-a-thinkpad-helix2-tablet-not-really-going-well
where we found out out that up to Ubuntu 22.04 it all worked (sort off) and later versions it didn't.....nowhere.
I installed Ubuntu Unity 25.04 to see what touch-capabilities were available (not much actually) for the touch-screen and discovered the audio card did work if set extremely loud.
I ran 3.8.50 live but as always: Dummy output. 
I don't have access to the tablet today but will check during the weekend.