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a noob
Asked: 2024-10-06 22:27:32 +0800 CST

Problem with the password of the GNU Grub recovery mode

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So earlier today I decided that I would improve the security of my Ubuntu 22.04 device a bit by adding a password for the recovery mode(GNU Grub). I read a couple of blogs and I followed them step by step. After I was done I rebooted my system to test it out, only to find that I had been locked out of my device. I couldn't boot any option without it prompting me to enter a username and password. I did not know why this happened, but after a bit of research, I realised that I had forgotten to make an encrypted password and I had only did the last parts of the designated script, which was to make the system prompt you to enter the username and password every time you boot up recovery mode. I am now locked out of my device because of an unknown grub password. If you don't set a password for grub, is there a default password or something?

boot

1 Answers

  1. Best Answer

    You will need to boot the system from your install media USB device. (At least not the target OS.)

    Select trial Ubuntu.

    From a command prompt: -

    Identity the Ubuntu partition on your target disk

    sudo fdisk -l

    Then mount it (replace x & y with your Ubuntu details)

    mount /dev/sdxy /mnt

    Then goto the grub boot directory

    cd /mnt/boot/grub

    Edit the file as below using your preferred editor (I use vi).

    sudo vi ./grub.cfg

    Search for password and comment it out.

    # password topsecret

    Save file; sync the disk and unmount it. Then reboot.

    sync; sync
cd /
umount /mnt
reboot
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