Can't UEFI boot [Solved]

[kendew]

Wonder if anyone can help me with this as I'm trying to piece things together on what's new territory for me.
I have an Intel NUC, the NUC6CAYH and I really like the way it's running Stretch, but there are some issues I'm trying to correct. I can get this unit to boot in legacy mode fine but if I try to set it to boot in UEFI mode in the Intel Visual BIOS (0041) the system will not boot. A "no bootable device found" error appears on the screen and that's as far as it will go.
Looking around I found one person who fixed the error at https://itsfoss.com/no-bootable-device-found-ubuntu/ but he is dealing with an Acer laptop running Ubuntu which is different. He suggests finding the “Select an UEFI file as trusted for executing” option and selecting shimx64.efi.
In the BIOS I have I see no such option, “Select an UEFI file as trusted for executing”. I am wondering if anyone can guide me here. I understand UEFI boots faster and is more secure.
Kendew

[p.H]

I can get this unit to boot in legacy mode fine but if I try to set it to boot in UEFI mode in the Intel Visual BIOS (0041) the system will not boot. A "no bootable device found" error appears

An EFI-compatible boot loader must be installed in order to boot in EFI mode. If you installed in legacy mode, the installer only installed a BIOS-compatible boot loader. But you may install an EFI boot loader afterwards.

I understand UEFI boots faster and is more secure.

Debian stretch does not support secure boot, so you'd have to disable the secure boot which is not very secure anyway.
In my experience, EFI boot is not faster than legacy BIOS boot.
Also in my experience, most firmwares have more or less serious bugs with EFI boot.
If these are your only reasons to switch to EFI boot, my advice is to stick to legacy BIOS boot.

[kendew]

Thank you for your reply. I think I may take your advice. At the moment, after powering on the computer, it takes a full ten seconds or so before the grub screen appears (Intel Celeron J3455 CPU, quad-core, 1.5 GHz (2.3 GHz burst), 10W TDP). After grub, another 10 seconds or so before the LightDM login screen appears. I thought maybe EFI would speed this up, but my main issue was with security. If Stretch doesn't support secure boot they must have a reason and I wonder what it might be. Also, in BIOS there is an option to check "Fast Boot". I wonder if it is advisable to check this, and what it might be leaving out to boot fast.

[p.H]

You can enable fast boot and test the difference. At worst, the system won't boot.
If you want to test EFI boot, you can also install a GRUB EFI bootloader :
- create a partition of type "EFI" and size at least a few megabytes
- format it as FAT
- mount it on /boot/efi
- install the package grub-efi-amd64-bin
- install the boot loader in the removable device path

Code: Select all

grub-install --target=x86_64-efi --removable

It will not remove the GRUB BIOS bootloader.
If you do not have room for the extra partition on the disk, you can put it on a USB drive.
If the EFI firmware is 32 bit, install grub-efi-ia32-bin and use --target=i386-efi instead. If in doubt, you can install both.