It is possible to get into the BIOS doing the following:
1) Power off the stick
2) Press and hold the power button down for 3 seconds then release it.
3) The NUC will provide you with 5 options
It is possible to update the BIOS using a USB drive or microSD card.
-If you have a Bluetooth keyboard, follow the steps described on the link below:
The Boot Display options might be disable in the BIOS, so F2, F7 could not be working. Get into the BIOS>Configuration tab>Boot Display and enable the options.