On power up the DEL key will get you into the BIOS which has an American Megatrends Inc copyright message. At the top of the screen it's identified as the Aptio Setup Utility with a 2013 copyright. The 'Main' screen identifies it as BIOS version US310e v1.62 dated 04/01/2015.
Under the Advanced tab is an entry for CSM Configuration. This is the Compatibility Support Module Configuration and is where you setup UEFI and/or Legacy booting.
Elsewhere the Boot tab lets you setup the order of booting.
On power-up, if you wish to override the default booting behaviour, hitting the F7 key brings up a boot menu. (If an administrator password is set you have to enter that first). On my system with a Sandisk Cruzer Blade USB pen drive plugged in I got:
Please Select Boot DeviceUEFI: Built-in EFI Shell Realtek PXE B01 D00 UEFI: SanDisk Cruzer Blade 1.26 PO: mSATA mini 3ME4 UEFI: SanDisk Enter Setup↑ and ↓ to move selection
ENTER to select boot device
ESC to boot using defaults
You use the up/down arrow keys to select a particular entry and then hit Enter to boot it.
My unit came with the flash memory wiped clean. The NEC support site includes WES8 recovery files so I decided to to try a (re)installation of the standard software.
There are step-by-step instructions on the website. Essentially what is involved is:
It took just under 15 minutes to restore the OS on my US310e and then some more time 'Scanning and repairing drive (c:)' on first boot.