It seems Intel has been busy releasing BIOS updates for the Bay Trail NUC DN2820FYKH the last 30 days or so. Anyhow, BIOS version 45 just surfaced. Not that many changes here, but in case you missed the one week older version 43, that had quite a few changes. Details are available in the Release notes document.
Download the BIOS at Intel’s download center here, copy the .BIO file on an USB stick, plug it in and press F7 at boot to start the upgrade.