Before you try to update, you need to find out which version of Unitiqute you have - if it’s an early one it may well not be upgradeable. See this post;
Update from Naim:
Just to confirm firmware 4.9 is now available for customers to update their products to switch from vTuner to Naim Radio - https://media.focal-naim.com/naim/file_manager_files/pages/legal/updates/streaming-products2.pdf
Mu-so Gen 1, firmware 2.1.0 is live although, it may be filtering through the system for some, and this is for the naim radio update. I’ve checked update works here ok.
No other changes have gone into these releases.
We have also made available 7.3.0 APPs to…