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I messed up the EFI partition and now when I boot my computer it opens the BIOS interface without any boot option, as if my disk has been erased. However using a live USB (which is correctly recognised and booted) and using grub command line I've been able to boot my principal OS (Ubuntu). However I don't know how to fix this problem. I've tried running grub-install /dev/sda but it didn't changed anything.

The EFI partition seems completely fine: it has the correct flag (esp, boot) and there are all the correct files inside.

tree /boot/efi/ └── EFI ├── Boot │ └── bootx64.efi ├── Microsoft │ ├── Boot │ ..... └── ubuntu ├── fbx64.efi ├── fw ├── fwupx64.efi ├── grub.cfg ├── grubx64.efi ├── mmx64.efi └── shimx64.efi

What I should check? What I'm missing?

This is my partition table:

parted /dev/sda print Model: ATA Crucial_CT525MX3 (scsi) Disk /dev/sda: 525GB Sector size (logical/physical): 512B/512B Partition Table: gpt Disk Flags: Number Start End Size File system Name Flags 1 1049kB 1612MB 1611MB fat32 EFI System Partition boot, esp 2 1612MB 87.9GB 86.3GB ext4 Ubuntu 3 87.9GB 281GB 193GB ext4 Home 5 290GB 290GB 16.8MB Microsoft reserved partition msftres 6 290GB 405GB 115GB ntfs Basic data partition msftdata 8 405GB 500GB 94.4GB ntfs Data msftdata 9 500GB 525GB 25.3GB ext4 Backup OS
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6 Answers 6

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I had to rename /EFI/my-custom-label/grubx64.efi to /EFI/boot/bootx64.efi for my Asus UEFI BIOS to start recognizing it.

This problem occurred on Asus Maximus VII Impact (Z97 chipset). My friend has a similar issue on an Z87-based Asus motherboard.

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  • Life saver! Windows Recovery messed up my Linux (actually Android x86) bootable USB. I had to set partition type to ESP / ef with DISKPART eg. set id=ef override and active, but it still didn't work until I renamed \EFI\BlissOS\BOOTx64.EFI to \EFI\boot\bootx64.efi (note lowercase file name as well).:Thanks for the tip, seems Window Recovery renamed files/folders along with disabling filesystem type. At least I learned something new, hopefully this comment helps other in same situation! Commented Apr 6 at 8:21
  • Phew... this also saved my install on my Gigabyte mainboard. Thanks! Did introduce an error on startup error: no such device: /.disk/info because grub expects the old EFI/debian directory (I moved the whole folder to EFI/Boot as that was the folder for my Windows 10 installation); so I'm now duplicating to EFI/debian and renaming to grubx64.efi in that folder. Should just beware of messups in case grub updates 🥴 Commented Sep 7 at 16:19
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My guess is your EFI system variables aren't being set to point to the right bootloader. The program you want to check this is efibootmgr. This will show you all of the boot entries stored in NVRAM.

In theory, grub-install should handle this, but you may not be passing the right options. This sample command SHOULD work:

grub-install --target=x86_64-efi --efi-directory=ESP_MOUNT_PATH --bootloader-id=grub

Change ESP_MOUNT_PATH to the path of your EFI dir.

If this doesn't work, you can try using efibootmgr directly: 

efibootmgr --create --disk /dev/sda --part 1 --loader /EFI/ubuntu/grubx64.efi --label "GRUB"

I think on some systems you may have to use /EFI/ubuntu/shimx64.efi. So try something like this and see what works.

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  • I've tried both the commands: they worked correctly (the second had created a new boot entry which i can display trough efibootmgr ) however when I turn on my pc I get to the BIOS screen with no boot options Commented Apr 21, 2017 at 9:46
  • Couple things: * it LOOKS ok, but can you print /dev/sda's partition table in gdisk, to make sure that has the correct partition type: EF00? * Also, check in your BIOS settings for things like 'Legacy Boot', or CSM (Compatability Support Module) - try disabling those, to force the BIOS to ONLY go for GPT/EFI boot, and totally skip its MBR booting logic - see if that helps. * Do you have any other hard drives, that may have another EFI system partition on them? Commented Apr 21, 2017 at 22:06
  • This is exactly what I was looking for, thanks. Commented Nov 6, 2024 at 8:01
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There is another issue that can cause this, which I have recently hit.

To detect this issue, boot from a Linux live and run gdisk /dev/sd[whatever-your-disk-is] , usually /dev/sda or /dev/sdb or /dev/sdc .

Give the p command to ensure you see the right list of partitions (if not, this might not be your disk).

Then give the v command. And it might respond with this:

Warning: The 0xEE protective partition in the MBR is marked as active. This is technically a violation of the GPT specification, and can cause some EFIs to ignore the disk, but it is required to boot from a GPT disk on some BIOS-based computers. You can clear this flag by creating a fresh protective MBR using the 'n' option on the experts' menu.

If this is the response, use the commands: e, n, w. Then reboot and you might have your EFI back!

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    This fixed my issue! One note: For my installation, to get to the expert menu in gdisk I needed to press 'x' instead of 'e'. FWIW, I was following these instructions when I encountered this issue: redhat.com/sysadmin/bios-uefi. My disk was already using GPT, but I wanted to switch from BIOS to UEFI boot. Commented May 18, 2022 at 17:40
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I resolved the problem simply formatting the partition (FAT32 with boot flag as obviously), mounting it and running grub-install. Then I had only to update the UUID in /etc/fstab. For Windows I had to use a USB with the installer and use the utility bcdboot to rewrite the EFI.

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I also had grub not showing all partitions when booting with EFI, adding the parameter --modules="part_gpt part_msdos" to grub-install allowed it to show all partitions with ls and ls -l.

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In my case I had to run gdisk to write a GPT instead of an MBR to the disk.

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    It does appear that the OP has: "Partition Table: gpt" Commented Jan 4, 2021 at 21:00
  • You're right, I missed that in the output of parted. But maybe I'll leave that here, because for me that solved the issue when I had the very same symptoms. Commented Jan 4, 2021 at 22:32

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