Ubuntu MATE 24.04
Title says it all.Not my primary machine but still a stupid mistake while reformatting a partition on a USB stick I wasn’t paying attention and the boot partition on the ssd drive is now empty. I can get in with a live USB but don’t really know what to do from there.
Hi, @Norm24!
Sorry to hear that 
When you say that you “accidentally reformatted efi boot partition”, did you change its filesystem type or did you “only” erase its contents? Is that computer running only “Ubuntu MATE 24.04” or are you “dual booting” it with any other Operating System (Windows, another Linux distribution…)?
If you boot from your live USB “Ubuntu MATE 24.04” flash drive, and then open a “MATE terminal” session, could you please run the following command and reply with the output?
sudo parted -l
Reformatted the boot partition and changed the filesystem type but was able on my own to get a certain point.
Here’s the output of sudo parted -l:
ubuntu-mate@ubuntu-mate:~$ sudo parted -l
Model: ATA SK hynix SC210 m (scsi)
Disk /dev/sda: 256GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 1049kB 1128MB 1127MB fat32 boot, esp
2 1128MB 256GB 255GB ext4
Model: SanDisk Cruzer Glide (scsi)
Disk /dev/sdb: 30.8GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 32.8kB 4513MB 4513MB ISO9660 hidden, msftdata
2 4513MB 4519MB 5202kB Appended2 boot, esp
3 4519MB 4519MB 307kB Gap1 hidden, msftdata
4 4519MB 30.8GB 26.3GB ext4
OK. Good. So /dev/sda is currently your 256 GB SSD and /dev/sdb is your 32 GB live USB Flash drive, right?
So, the ESP (EFI System Partition) in /dev/sda is in the right place (first partition) and has the right filesystem type (FAT32). Good 
Could you please run the following commands in the same MATE Terminal Session?
sudo mkdir -pv /mnt/boot/efi
sudo mount /dev/sda1 /mnt/boot/efi
sudo mount /dev/sda2 /mnt
And then, please run the following commands and paste the output:
sudo ls -al /mnt/boot
sudo ls -al /mnt/boot/efi
sudo ls -al /mnt/boot/efi/EFI
sudo ls -al /mnt/boot/efi/EFI/Boot
sudo ls -al /mnt/boot/efi/EFI/ubuntu
Bummer. I’ve been there as well.
Looks like Ricardo’s got you on the right track here. Hope this has a happy outcome. 
Yes.
Output for sudo ls -al /mnt/boot:
ubuntu-mate@ubuntu-mate:~$ sudo ls -al /mnt/boot
total 292184
drwxr-xr-x 4 root root 4096 Apr 13 20:37 .
drwxr-xr-x 23 root root 466944 Apr 13 21:09 ..
-rw------- 1 root root 9125925 Mar 6 00:43 System.map-6.8.0-106-generic
-rw------- 1 root root 9125925 Mar 13 13:27 System.map-6.8.0-107-generic
-rw------- 1 root root 9126224 Mar 19 11:44 System.map-6.8.0-110-generic
-rw-r--r-- 1 root root 287601 Mar 6 00:43 config-6.8.0-106-generic
-rw-r--r-- 1 root root 287601 Mar 13 13:27 config-6.8.0-107-generic
-rw-r--r-- 1 root root 287605 Mar 19 11:44 config-6.8.0-110-generic
drwxr-xr-x 2 root root 4096 Aug 19 2024 efi
drwxr-xr-x 6 root root 4096 Apr 13 20:37 grub
lrwxrwxrwx 1 root root 28 Apr 13 20:37 initrd.img -> initrd.img-6.8.0-110-generic
-rw-r--r-- 1 root root 74906140 Mar 24 12:18 initrd.img-6.8.0-106-generic
-rw-r--r-- 1 root root 74904297 Apr 10 00:27 initrd.img-6.8.0-107-generic
-rw-r--r-- 1 root root 74918102 Apr 13 20:37 initrd.img-6.8.0-110-generic
lrwxrwxrwx 1 root root 28 Apr 13 20:37 initrd.img.old -> initrd.img-6.8.0-107-generic
-rw-r--r-- 1 root root 142796 Apr 8 2024 memtest86+ia32.bin
-rw-r--r-- 1 root root 143872 Apr 8 2024 memtest86+ia32.efi
-rw-r--r-- 1 root root 147744 Apr 8 2024 memtest86+x64.bin
-rw-r--r-- 1 root root 148992 Apr 8 2024 memtest86+x64.efi
lrwxrwxrwx 1 root root 25 Apr 13 20:37 vmlinuz -> vmlinuz-6.8.0-110-generic
-rw------- 1 root root 15034760 Mar 6 06:23 vmlinuz-6.8.0-106-generic
-rw------- 1 root root 15042952 Mar 13 17:46 vmlinuz-6.8.0-107-generic
-rw------- 1 root root 15042952 Mar 19 13:43 vmlinuz-6.8.0-110-generic
lrwxrwxrwx 1 root root 25 Apr 13 20:37 vmlinuz.old -> vmlinuz-6.8.0-107-g
Output for sudo ls -al /mnt/boot/efi:
ubuntu-mate@ubuntu-mate:~$ sudo ls -al /mnt/boot/efi
total 8
drwxr-xr-x 2 root root 4096 Aug 19 2024 .
drwxr-xr-x 4 root root 4096 Apr 13 20:37 ..
Output for sudo ls -al /mnt/boot/efi/EFI
sudo ls -al /mnt/boot/efi/EFI
ls: cannot access '/mnt/boot/efi/EFI': No such file or directory
ubuntu-mate@ubuntu-mate:~$
Output for sudo ls -al /mnt/boot/efi/EFI/Boot:
ubuntu-mate@ubuntu-mate:~$ sudo ls -al /mnt/boot/efi/EFI/Boot
ls: cannot access '/mnt/boot/efi/EFI/Boot': No such file or directory
ubuntu-mate@ubuntu-mate:~$
And finally sudo ls -al /mnt/boot/efi/EFI/Ubuntu
ubuntu-mate@ubuntu-mate:~$ sudo ls -al /mnt/boot/efi/EFI/Ubuntu
ls: cannot access '/mnt/boot/efi/EFI/Ubuntu': No such file or directory
That’s great, @Norm24
Please run the following commands in the same MATE Terminal session:
sudo mount --bind /dev /mnt/dev
sudo mount --bind /proc /mnt/proc
sudo mount --bind /sys /mnt/sys
sudo chroot /mnt
mount -t efivarfs none /sys/firmware/efi/efivars
grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=ubuntu
Please, paste the output of the last command (so, the output of the “grub-install” command above) and then run the following commands and paste the outputs:
ls -al /boot/efi
ls -al /boot/efi/EFI/Boot
ls -al /boot/efi/EFI/ubuntu
Output for grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=ubuntu:
root@ubuntu-mate:/# mount -t efivarfs none /sys/firmware/efi/efivars
root@ubuntu-mate:/#
grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=ubuntu
Installing for x86_64-efi platform.
grub-install: error: /boot/efi doesn't look like an EFI partition.
Output for ls -al /boot/efi
root@ubuntu-mate:/# ls -al /boot/efi
total 8
drwxr-xr-x 2 root root 4096 Aug 19 2024 .
drwxr-xr-x 4 root root 4096 Apr 13 16:37 ..
Output for ls -al /boot/efi/EFI/Boot:
root@ubuntu-mate:/# ls -al /boot/efi/EFI/Boot
ls: cannot access '/boot/efi/EFI/Boot': No such file or directory
And finally ls -al /boot/efi/EFI/ubuntu:
root@ubuntu-mate:/# ls -al /boot/efi/EFI/ubuntu
ls: cannot access '/boot/efi/EFI/ubuntu': No such file or directory
That’s weird Could you please run the following commands in that same MATE Terminal session and paste the outputs:
parted -l
df -hTP
ls -al /boot/grub
output for parted -l:
root@ubuntu-mate:/# parted -l
Model: ATA SK hynix SC210 m (scsi)
Disk /dev/sda: 256GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 1049kB 1128MB 1127MB fat32 boot, esp
2 1128MB 256GB 255GB ext4
Model: SanDisk Cruzer Glide (scsi)
Disk /dev/sdb: 30.8GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 32.8kB 4513MB 4513MB ISO9660 hidden, msftdata
2 4513MB 4519MB 5202kB Appended2 boot, esp
3 4519MB 4519MB 307kB Gap1 hidden, msftdata
4 4519MB 30.8GB 26.3GB ext4
output for df -hTP:
root@ubuntu-mate:/# df -hTP
Filesystem Type Size Used Avail Use% Mounted on
/dev/sda2 ext4 233G 45G 177G 21% /
none efivarfs 128K 63K 61K 51% /sys/firmware/efi/efivars
and finally ls -al /boot/grub:
root@ubuntu-mate:/# ls -al /boot/grub
total 2420
drwxr-xr-x 6 root root 4096 Apr 13 16:37 .
drwxr-xr-x 4 root root 4096 Apr 13 16:37 ..
drwxr-xr-x 2 root root 4096 Aug 19 2024 fonts
-rw------- 1 root root 12393 Apr 13 16:37 grub.cfg
-rw-r--r-- 1 root root 1024 Apr 13 10:05 grubenv
drwxr-xr-x 2 root root 4096 May 21 2025 locale
drwxr-xr-x 2 root root 4096 Sep 14 2024 themes
-rw-r--r-- 1 root root 2411806 May 21 2025 unicode.pf2
drwxr-xr-x 2 root root 24576 May 21 2025 x86_64-efi
Hmm… So, apparently, /boot/efi did not get mounted. OK. Then, please run the following commands, in that same MATE Terminal session:
mount -v /dev/sda1 /boot/efi
grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=ubuntu
Please, paste the output of the above commands and then run the following commands and paste the outputs:
ls -al /boot/efi
ls -al /boot/efi/EFI
ls -al /boot/efi/EFI/Boot
ls -al /boot/efi/EFI/ubuntu
Output mount -v /dev/sda1 /boot/efi:
root@ubuntu-mate:/# mount -v /dev/sda1 /boot/efi
mount: /dev/sda1 mounted on /boot/efi.
Output grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=ubuntu:
root@ubuntu-mate:/# grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=ubuntu
Installing for x86_64-efi platform.
Installation finished. No error reported.
output ls -al /boot/efi:
root@ubuntu-mate:/# ls -al /boot/efi
total 12
drwxr-xr-x 3 root root 4096 Dec 31 1969 .
drwxr-xr-x 4 root root 4096 Apr 13 16:37 ..
drwxr-xr-x 4 root root 4096 Apr 13 20:16 EFI
output ls -al /boot/efi/EFI:
root@ubuntu-mate:/# ls -al /boot/efi/EFI
total 16
drwxr-xr-x 4 root root 4096 Apr 13 20:16 .
drwxr-xr-x 3 root root 4096 Dec 31 1969 ..
drwxr-xr-x 2 root root 4096 Apr 13 20:16 BOOT
drwxr-xr-x 2 root root 4096 Apr 13 20:16 ubuntu
output ls -al /boot/efi/EFI/Boot :
root@ubuntu-mate:/# ls -al /boot/efi/EFI/Boot
total 1884
drwxr-xr-x 2 root root 4096 Apr 13 20:16 .
drwxr-xr-x 4 root root 4096 Apr 13 20:16 ..
-rwxr-xr-x 1 root root 966664 Apr 13 20:16 BOOTX64.EFI
-rwxr-xr-x 1 root root 88344 Apr 13 20:16 fbx64.efi
-rwxr-xr-x 1 root root 856280 Apr 13 20:16 mmx64.efi
and finally ls -al /boot/efi/EFI/ubuntu:
root@ubuntu-mate:/# ls -al /boot/efi/EFI/ubuntu
total 4404
drwxr-xr-x 2 root root 4096 Apr 13 20:16 .
drwxr-xr-x 4 root root 4096 Apr 13 20:16 ..
-rwxr-xr-x 1 root root 108 Apr 13 20:16 BOOTX64.CSV
-rwxr-xr-x 1 root root 126 Apr 13 20:16 grub.cfg
-rwxr-xr-x 1 root root 2660232 Apr 13 20:16 grubx64.efi
-rwxr-xr-x 1 root root 856280 Apr 13 20:16 mmx64.efi
-rwxr-xr-x 1 root root 966664 Apr 13 20:16 shimx64.efi
Excellent, @Norm24! It seems that you’re ready to go! You can now shut down your live session and, when the computer has powered off, remove your USB Flash drive and power the computer back on and please tell us if the machine then powers on correctly.
Back in business!
Only caveat is that the boot process took much longer than usual and the grub timeout has reset itself to something 2 seconds.
That’s great, @Norm24! I’m glad I was able to help Thanks for reporting back. It’s now 1H30 A.M. here in Portugal and so I’m going to bed now, but maybe someone else can help you to understand why booting took muck longer. May I suggest that you do another reboot to see if that next boot is also slower than it used to be?
Restart was just as slow and I got this screen:
Doing Ctrl-D allowed to boot into the desktop but it to took quite a bit of time.
With the accidental reformat maybe the /etc/fstab still has the old UUID for the original EFI partition.
Press enter on that screen and run sudo blkid /dev/sda1 to get the new UUID for your EFI partition. Make sure it matches with whats in cat /etc/fstab
(post deleted by author)
I did it once too, but I wiped the disc and started over. It is why I keep good backups.
