When you have many disks, and you install many operating system, you may faced with a problem. That is your system’s EFI file will be stored in a different disk rather than your root disk. Also, you may accidentally delete system’s EFI file in a different disk. Here is how you can fix it.
Warning
This article is not a step-by-step guide!
All the commands in this article are very dangerous.
Think carefully and check your command before you press Enter.
Do it with your own risk!
I am not in response for your data loss.
Migrate EFI file to same disk
I assume that you have two disk: nvme0n1 and nvme1n1. Use lsblk command to know your disks.
Here is a correct sample. Fedora are on nvme0n1 and Ubuntu on nvme1n1:
➜ sudo lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
nvme0n1 259:3 0 931.5G 0 disk
├─nvme0n1p1 259:4 0 512M 0 part
└─nvme0n1p2 259:5 0 931G 0 part
nvme1n1 259:0 0 465.8G 0 disk
├─nvme1n1p1 259:1 0 512M 0 part /boot/efi
└─nvme1n1p2 259:2 0 465.3G 0 part /
But sometimes, your EFI file will be stored into a different disk like this:
➜ sudo lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
nvme0n1 259:3 0 931.5G 0 disk
├─nvme0n1p1 259:4 0 512M 0 part /boot/efi
└─nvme0n1p2 259:5 0 931G 0 part
nvme1n1 259:0 0 465.8G 0 disk
├─nvme1n1p1 259:1 0 512M 0 part
└─nvme1n1p2 259:2 0 465.3G 0 part /
You EFI file is stored in /dev/nvme0n1p1, not /dev/nvme1n1p1.
If you want to migrate efi file from /dev/nvme0n1p1 to /dev/nvme1n1p1, it’s easy.
The basic concept is:
- format disk rightly
- mount both part
- move files
- update
/etc/fstab
EFI partition should be in FAT32. Here is how you can format it:
sudo mkfs.fat -F32 /dev/nvme1n1p1
In most cases, the install software has already format it for you. It just pick a wrong disk partition. But you can still use this command to get a clear EFI partition.
After you get a right partition, mount it:
sudo mount /dev/nvme1n1p1 /mnt/boot
Then copy all the files from /boot/efi/ to /mnt/boot:
sudo cp -r /boot/efi/* /mnt/boot
After you copy the efi files, you still need to edit /etc/fstab to mount correct disk when system reboot.
sudo vim /etc/fstab
The origin config will be like this:
UUID=9D4C-93FE /boot/efi vfat umask=0077 0 1
Use blkid to get uuid:
➜ sudo blkid
/dev/nvme0n1p1: UUID="9D4C-93FE" BLOCK_SIZE="512" TYPE="vfat" PARTLABEL="EFI System Partition" PARTUUID="c5c9cac8-7a1b-47f7-a020-7e9d3d278c75"
/dev/nvme0n1p2: UUID="16461f63-c03e-4dd4-a032-9ef49ee48854" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="fb46775f-4538-4fa3-a909-7f37c5c59f1d"
/dev/nvme1n1p2: UUID="72d8bf22-bd3f-48e5-aeab-10604f83d254" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="0e2c65f1-4cb3-4121-8a81-22b5bdd8f28b"
/dev/nvme1n1p1: UUID="134D-9AFB" BLOCK_SIZE="512" TYPE="vfat" PARTLABEL="EFI System Partition" PARTUUID="b110cd31-bd24-4566-b986-6c57a97ffe73"
➜ sudo blkid /dev/nvme1n1p1
/dev/nvme1n1p1: UUID="134D-9AFB" BLOCK_SIZE="512" TYPE="vfat" PARTLABEL="EFI System Partition" PARTUUID="b110cd31-bd24-4566-b986-6c57a97ffe73"
The /dev/nvme0n1p1 partition will be mounted to /boot/efi. Change the UUID to /dev/nvme0n1p1. Just like this:
UUID=134D-9AFB /boot/efi vfat umask=0077 0 1
Then the system will try to mount /dev/nvme1n1p1 into /boot/efi.
Reboot your system to check if system mount right partion:
sudo reboot
Restore EFI files with grub
If you have already delete the entire disk which store your EFI files, here is how you can restore them.
The basic concept is:
- Boot from live cd
- Recreate a EFI partition
- Mount root partition
- Mount EFI partition
- Mount /dev, /proc, and /sys
- Chroot into it
- Run
grub-install - Edit
/etc/fstab - Umount everything
- Reboot your system
First you need a EFI partition, use fdisk to create a partition and format it:
sudo mkfs.fat -F32 /dev/sda1
Mount the root directory:
sudo mount /dev/sda2 /mnt
Mount the EFI partition:
sudo mount /dev/sda1 /mnt/boot/efi
Mount /dev and other necessary part:
sudo mount --bind /dev /mnt/dev/
sudo mount --bind /proc /mnt/proc/
sudo mount --bind /sys /mnt/sys/
Chroot into your system:
sudo chroot /mnt
You can use ls to check if you mount the right partition.
Then you can recreate EFI files with grub:
sudo grub-install /dev/sda
If this process did’t give you any error, the EFI files are restored.
Then you need to update /etc/fstab
sudo vim /etc/fstab
Use blkid to get disk uuid and mount the correct uuid like what I say before.
Then exit back to live cd system:
exit
Umount everything:
sudo umount /mnt/dev
sudo umount /mnt/proc
sudo umount /mnt/sys
sudo umount /mnt/boot/efi
sudo umount /mnt
Reboot your system:
sudo reboot