Using Bluetooth keyboard and mouse to enter BIOS is not supported.
When using a Bluetooth keyboard, pressing F2 does not allow me to enter the BIOS.
Bluetooth devices require drivers to be loaded after the Operating System (OS) loads. Until the OS loads, the Bluetooth Keyboard and Mouse will not be able to connect to the Intel® NUC.
To work around this limitation, connect a USB keyboard and mouse to your Intel® NUC when you need to configure BIOS settings.