Question – Cannot boot to the Boot Device Menu ?

As you’d expect from something so old, the USB drive must be pretty small to be recognized, try 32GB or less and FAT32 (FAT16 is supported up to 2GB)

Only one partition on any disk can be the active one and you don’t use any boot menu to change it, but some disk partitioning utility. If it’s just a BIOS file on an otherwise empty drive then that’s not supposed to be bootable.

The built-in EZ Flash 2 utility is outside of the BIOS and accessed with ALT-F2 during POST instead of the DEL you would use to enter the BIOS. There’s supposed to be a message at the bottom of the screen to indicate this, but modern monitors may not auto-resize quickly enough to see it.

In their infinite wisdom Microsoft have decided Windows never breaks so have disabled the F8 boot menu.
To restore the F8 functionality of previous versions of Windows,
Open an administrator Command Prompt and enter:
bcdedit /set {default} bootmenupolicy legacy
You will receive the message “The operation completed successfully”
That should make getting to the startup menu much easier in the future, but it still won’t let you boot from a non-active partition