Recovery from a bootable USB drive

How to boot from a bootable Recovery USB and recover the boot loader.
This is useful if you cannot boot your Operating System from disk.
Please note: You can follow this guide to create a bootable USB drive.

1 Cannot boot

If you can't access your operating system or its recovery menu, it can be repaired from a bootable USB drive.
Firstly, insert the USB drive and turn on your computer whilst repeatedly tapping the F7 key.
This will bring up the boot menu.

2 Boot Recovery USB

Use the arrow keys to select your USB drive and press enterto boot from it. You need to use the live mode of the USB. There are a few different terminologies used but typically it is Live, Tryor **Start.**On Ubuntu, the option to select is Try Ubuntu.

3 Check disk path

Open the GNOME Launcher and open Terminal.
To check the path of the disk, type in the below command:

sudo fdisk -l | grep nvme

4 Partition of disk

This will reveal the partition of the disk that needs mounting.

5 Mount partitions

Most installs will only have the 2 partitions shown.
Run the below commands to mount them:

mount /dev/nvme0n1p2 /mnt
mount /dev/nvme0n1p1 /mnt/boot

6 Enable network

Depending on what you need to do in the recovery mode, you may want to enable internet access with:

sudo cp /etc/resolv.conf /mnt/etc/resolv.conf

7 Connecting to installation

From here, we need to chroot into the disk with:

sudo chroot /mnt /bin/bash

8 Connected to installation

This will take you to a terminal window running as rooton your SSD.

9 Ready to diagnose

From here we are ready to perform further diagnostics on the installation.

  • fsck - Check file system
  • GRUB Repair - Update bootloader
  • dpkg - Repair broken packages

See further guide on using recovery mode

Feb 23, 2021