The Legacy Boot setting is actually a checkbox on the Boot Priority screen (Boot > Boot Priority). The Glossary for NUC Aptio-V is here: NUC-AptioV-BIOS-Glossary.pdf (intel.com) - see page 41. I found the setting only by methodically opening every screen and option I could find, no matter how irrelevant it seemed. The values for Secure Boot, UEFI Boot and Legacy Boot that you can see on the Boot screen are just “information” - so cannot be changed from that screen, even though other items in the same list are for setting options! It is really obscure and confusing. Here are some screen shots from the Glossary.
