<SOLVED> No EFI After Windows Update

Questions about Grub, UEFI,the liveCD and the installer
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MCDELTAT
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<SOLVED> No EFI After Windows Update

Post by MCDELTAT »

I recently upgraded the hardware in my system significantly (moved from a 6700K on Z170 to 8700K on Z370). I didn't do anything at all to any of my disks. I was excited to see that Windows booted immediately. Next was Linux but the Grub menu didn't appear. I check the UEFI/BIOS menu and I had a selection for my whole SSD, but it does nothing.

Booted into a Mint Live USB in UEFI Mode. Ran recommended settings on boot-repair. Nothing.

I mounted my Mint 18.2 partition which was on /sda6 on /mnt. From what I can tell the grub.cfg file looks perfectly fine, with all the regular menus I would want to see for the Linux 18.2 Options and the Windows Boot Manager.

Something that seems strange however is that I don't have any files in /boot/efi/ Shouldn't I have my bootable .efi files in there that are the targets of the grub loader? How do I get them back?

My plan was to clean install anyways given such a large hardware change but out of curiosity I wanted to benchmark the system before I make any changes so they can all be measurable.
Last edited by MCDELTAT on Thu Nov 16, 2017 6:46 am, edited 1 time in total.
fabien85
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Re: No EFI After Windows Update

Post by fabien85 »

so sda6 is your / partition which contains most of the system.
The EFI bootloaders are located in a separate partition, the so-called EFI System Partition (ESP), and when you have a normal linux boot, this partition is mounted at /boot/efi
That explains why you would see the EFI files on /boot/efi on a normal boot, but you dont see them at the moment if you just mount sda6.
The ESP normally contains both the windows bootloader and grub, so if you can still boot windows (and furthermore if you say you didnt touch the drives), then this partition is intact. It's probably either sda1 or sda2, you can check with gparted, it's a small (50-500MB) FAT32 partition with the flags "boot" and "esp".

I dont know exactly what "moved from a 6700K on Z170 to 8700K on Z370" means, but if you changed the motherboard or made changes that cut power to the NVRAM, then the boot entries have been reset to default, and nearly all manufacturers configure the default to be booting windows. In other words, the firmware/BIOS doesnt know anymore where grub is located.
One well-documented way to fix that is to fully reinstall grub : https://sites.google.com/site/easylinuxtipsproject/6
Other way is to recreate an NVRAM entry pointing to EFI/ubuntu/shimx64.efi (or grubx64.efi) on the ESP. Some manufacturers provide an option for doing that directly in the firmware interface ; otherwise you could do it manually with efibootmgr from Linux or bcdedit from windows. Yet another method is to use a software in windows like easyUEFI's free version.
MCDELTAT
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Re: No EFI After Windows Update

Post by MCDELTAT »

Thanks for your help. Decided to clean install anyway because I had already spent 3 hours on it when I can get back up and running from clean in about 30 minutes. I kept Windows around and just cleared out my /sda6 partition that held Linux. Then the installer took care of getting GRUB back to how it should be.

What I meant to say is that I built my PC, and so I moved from an Intel 6700K CPU to an 8700K, which just came out last month.
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