I just recently came across this thread on the Jellyfin forums where @TheDreadPirate wrote an excellent guide on how to update the ARC firmware on linux.
I followed this specific post for my Sparkle A310 Eco and the fan isn’t ramping up and down anymore!
My feature request is still relevant (or so I think) as temperature and fan speed reporting (and control) would still be very useful for monitoring or maybe noise tuning.