Steps to reproduce :
I upgraded th BIOS and loaded standard values using F9.
SAved using F10
Changed some values like FANLESS option.
When I restarted my FAN is still running.
Checked BIOS and it is still showing FANLESS option selected.
Same is happening with Turbo boost, can't disable it and probably other options
Please update your Bios again, however, this time using Bios Recovery procedure (you may use the Recovery form Power Button Menu, since it doesn't require opening the NUC):