grub (Ubuntu) boot menu missing option to go to EFI BIOS
entry is missing because the ubuntu installer was booted using the Compatibility
Support Module (CSM) to emulate a bios only system.
When booting from a device on a usb stick, there are usually two boot menu
entries. One for booting in efi mode, and one for booting in compatibility
mode. The labeling varies depending the the uefi manufacturer and version.
If the install was done in compatibilty mode, it will have to be redone, being
careful to select efi mode, if desired but that is not necessary for booting from
a usb stick.
Which key is used to trigger showing the boot menu varies between firmware
manufacturers. It’s using either f8 or f12, but may be something else. The
documentation for that system should indicate which key or key combo is
needed.
Try repeatedly pressing and releasing f8 starting immediately after booting
shows anything on the screen. If it doesn’t show the menu, reboot and try
a different function key.
Note that the boot menu will only show the usb device(s) if they have a
bootable usb stick present at boot.
Regards, Dave Hodgins
Read more here: Source link