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Accepted
xkeshav
Asked: 2024-10-08 12:01:30 +0800 CST

Screen stuck on grub after trying os-uninstaller, boot selection menu not appears with dual boot system

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I have windows and ubuntu24.04 and tried ti remove windows os completely and for that used os-uninstaller, it choose windows and somewhere stuck whicl rewrite GRUB command and then I restart the computer and now grub screen comes

I am sure that windows partition might be corrupted but ubuntu is still safe and when try to check with ls

ls (hd0,gpt1)

output

efi/ System Volume information

so how can we edit grub so that it will start ubuntu .

Here is how all partition ls output looks like grub screen

Thanks

Update

After following some post I tried to set prefix but there is no boot folder so set

set root=(hd0,gpt1)
set prefix=(hd0,gpt1)/efi/boot/grub

and when run set

it gives below output grub set command output

after that I do exit and windows starts but ubuntu is not working no boot menu appears at all

boot

1 Answers

  1. Best Answer

    Here’s a summarized version of the main commands and steps to recover from a deleted OS situation using a live USB environment, including troubleshooting for common issues like disk space:

    Prerequisites:

    • Bootable Ubuntu 24.04 live USB. ( although I has 23.10 USB while system installed was 24.04 but it worked)

    1 Mount partitions

    1. Boot into the live USB and open a terminal.

    2. Identify the partitions:

    sudo fdisk -l

    You will see 2 partition, one is EFI ( sometimes it is not there ) and one is Linux FileSystem

    Device             Start       End   Sectors   Size Type
/dev/nvme0n1p1      2048    206847    204800   100M EFI System
/dev/nvme0n1p2    206848    239615     32768    16M Microsoft reserved
/dev/nvme0n1p3    239616 211358180 211118565 100.7G Microsoft basic data
/dev/nvme0n1p4 211359744 294244351  82884608  39.5G Microsoft basic data
/dev/nvme0n1p5 294246400 295315455   1069056   522M Windows recovery environment
/dev/nvme0n1p6 295315456 500115455 204800000  97.7G Linux filesystem
    1. Mount the root partition (replace /dev/nvme0n1p6 with your actual root partition):
    sudo mount /dev/nvme0n1p6 /mnt
    1. If there's an EFI partition (typically small, like 100MB):
    sudo mount /dev/nvme0n1p1 /mnt/boot/efi

    2 Copy data from os_deleted to root

    actually the os-uninstaller software moved files from root partition to os_deleted and hanged which is causing the boot issue

    you can check whether /etc, /proc, /sys, /run directories are under root partition (i.e. /dev/nvme0n1p1 ) or not and if these directory are under os_deleted folder then we have to follow below steps.

    1. If your data was moved to os_deleted:
    sudo rsync -av /mnt/os_deleted/ /mnt/

    This command copies the contents of os_deleted back to the root partition.

    If "No space left on device" error occurs:

    Remove large or unnecessary files:

    sudo rm -rf /mnt/var/cache/apt/*
sudo rm -rf /mnt/var/log/*

    Use find to locate large files:

    sudo find /mnt -type f -size +100M

    Then remove any unnecessary large files:

    sudo rm /mnt/path/to/large/file

    in my cae there are images and video files so removed those

    3 chroot into the system

    1. Bind the required directories:
    sudo mount --bind /dev /mnt/dev
sudo mount --bind /proc /mnt/proc
sudo mount --bind /sys /mnt/sys
sudo mount --bind /run /mnt/run
    1. Enter the chroot environment:
    sudo chroot /mnt

    if above command gives error:

    failed to run command /bin/bash : No such file or directory means you do not have all required files in root directory

    you can run sudo fsck /dev/nvme0n1p6 to check corrupted files

    it chroot works succesfully your shell prompt will be changed to root@root

    4 Reinstall GRUB

    1. Install GRUB for UEFI systems:
    grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=ubuntu
    1. Update the GRUB configuration:
    update-grub
    1. If you encounter "unable to allocate pty", run
    mount -t devpts none /dev/pts

    5 Exit chroot and unmount

    1. Exit chroot:
    exit
    1. Unmount the bound directories:
    sudo umount /mnt/dev
sudo umount /mnt/proc
sudo umount /mnt/sys
sudo umount /mnt/run
sudo umount /mnt/boot/efi  # If mounted
sudo umount /mnt

    6 Reboot

    1. Reboot the system to check if GRUB is restored:
    sudo reboot

    Troubleshooting tips:

    If "target is busy" during unmount, use:

    sudo umount -l /mnt

    To list processes using a mount point:

    sudo lsof +D /mnt
sudo fuser -vm /mnt
sudo fuser -k /mnt  # To kill processes

    Use rsync with --exclude to temporarily skip non-essential data if space is an issue:

    sudo rsync -av --exclude='home/*' /mnt/os_deleted/ /mnt/

    This should help for restoring the system and resolving common errors encountered during the process.

    Hope it helps

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