Repair Linux boot failures in GRUB 2 rescue mode
- Basic commands available. These are the commands that can be used when you enter the GRUB 2 terminl mode by pressing "c". Type help search for the available options.)
- The Rescue Shell. If you get a rescue shell, this usually means that GRUB failed to load the "normal" module for some reason.
- After Booting the system. Update the GRUB config file. This should be it for the rescue part and your system should be good and running.
How do I fix GRUB2 boot problems?
Boot Repair is a graphical tool that can repair GRUB2 with a single click. This is the ideal solution to boot problems for most users. If you have the media you installed Ubuntu from, insert it into your computer, restart, and boot from the removable drive.
What's new in GRUB 2?
As GRUB 2's ability to fix boot problems has greatly improved over the original GRUB bootloader. This article provides you with information on available options for repairing GRUB 2 boot issues and specific instructions on how to use the GRUB 2 terminal. The instructions are written for GRUB 2. How it looks?
Can I repair Ubuntu desktop with GRUB2?
Although we'll be using a Ubuntu Desktop live instance, the process will work, even if you're repairing, say, Fedora or CentOS. As the boot loader is GRUB2, you should be good to go--GRUB2 is the default boot loader in most Linux distributions.
How do I restore GRUB2 from a Ubuntu Live CD?
You can easily restore GRUB2 from a Ubuntu live CD or USB drive. This process is different from restoring the legacy GRUB boot loader on older Linux distributions. This process should work on all versions of Ubuntu. It’s been tested on Ubuntu 16.04 and Ubuntu 14.04. Boot Repair is a graphical tool that can repair GRUB2 with a single click.
How do I fix a corrupted grub?
The solutionTo fix the problem execute from grub command line: ... Restore boot partition on hd0,0 (first partition on first disk) as in above example from find command. ... Then setup grub on first disk (hd0) – as in above example boot stage1 is located on hd0. ... After command will succeed reboot the server.
How do I reinstall grub2 EFI?
Use chroot to install grub to the deviceEnter the RFS directory: $ cd /rfs.Create the EFI directory under boot: $ sudo mkdir -p boot/efi.Bind mount the /dev, /sys, and /proc directories. ... Bind mount the your EFI mount point directory: ... Enter the chroot jail: ... Install grub to your Linux partition.
How do I repair grub loader?
The graphical wayInsert your Ubuntu CD, reboot your computer and set it to boot from CD in the BIOS and boot into a live session. You can also use a LiveUSB if you have created one in the past.Install and run Boot-Repair.Click "Recommended Repair".Now reboot your system. The usual GRUB boot menu should appear.
How do I fix grub in terminal?
via Partition Files CopyBoot to the LiveCD Desktop.Mount the partition with your Ubuntu installation. ... Open a terminal by selecting Applications, Accessories, Terminal from the menu bar.Run the grub-setup -d command as described below. ... Reboot.Refresh the GRUB 2 menu with sudo update-grub.More items...•
How do I reinstall GRUB2 from rescue mode?
In order to reinstall GRUB2 you have to boot into rescue mode....Booting into rescue mode and reinstalling GRUB2Boot from the RHEL7 installation DVD by altering the boot order in Bios and selecting DVD media as the first booting preference. ... At the boot screen, Select the Troubleshooting option at the end of the screen.More items...
How do I restore a missing GRUB bootloader?
Steps to recover deleted GRUB bootloader in Linux:Boot into Linux using Live CD or USB Drive.Get into Live CD mode if available. ... Launch Terminal. ... Find Linux partition with working GRUB configuration. ... Create temporary directory to mount Linux partition. ... Mount Linux partition to the newly created temporary directory.More items...
How do I run boot repair?
Method 1: Startup Repair toolStart the system to the installation media for the installed version of Windows. ... On the Install Windows screen, select Next > Repair your computer.On the Choose an option screen, select Troubleshoot.On the Advanced options screen, select Startup Repair.More items...•
Can not install boot Repair?
Unable to install boot-repairBoot to LiveCD.Connect to Internet.Open terminal.Give command sudo add-apt-repository ppa:yannubuntu/boot-repair && sudo apt-get update.Then give command sudo apt-get install -y boot-repair && boot-repair.
How do I manually install grub bootloader?
Installing GRUB2 on a BIOS systemCreate a configuration file for GRUB2. # grub2-mkconfig -o /boot/grub2/grub.cfg.List block devices available on the system. $ lsblk.Identify the primary hard disk. ... Install GRUB2 in the MBR of the primary hard disk. ... Reboot your computer to boot with the newly installed bootloader.
How do I uninstall and reinstall GRUB?
Uninstalling GRUB 2Open a terminal: Applications, Accessories, Terminal.Optional: Make backup copies of the main GRUB 2 directories and files. sudo cp /etc/default/grub /etc/default/grub.old. ... Remove GRUB 2. sudo apt-get purge grub-pc. ... Install GRUB 0.97. ... With grub installed, the user must still create the menu. ... Reboot.
How do I get grub boot menu?
With BIOS, quickly press and hold the Shift key, which will bring up the GNU GRUB menu. (If you see the Ubuntu logo, you've missed the point where you can enter the GRUB menu.) With UEFI press (perhaps several times) the Escape key to get grub menu.
How do I use GRUB command line?
Booting From grub> The first line sets the partition that the root filesystem is on. The second line tells GRUB the location of the kernel you want to use. Start typing /boot/vmli , and then use tab-completion to fill in the rest. Type root=/dev/sdX to set the location of the root filesystem.
How do I reinstall EFI partition?
More secure way to restore EFI partition in Windows 10Select the system backup task and click "Next". ... Select to restore entire backup or a part and click "Next".Confirm operations on the “Operation Summary” page and click on “Start Restore” button.Restart your computer to boot from the original hard drive.
How do I manually install GRUB bootloader?
ResolutionMount root to /mnt. ... Mount /boot to /mnt/boot. ... Mount system pseudo file systems under /mnt. ... "change root" or chroot to /mnt. ... Under /boot/grub, there is a file called "device. ... Launch the grub interactive shell. ... In the interactive shell, you will see a "grub>" prompt. ... Type quit.More items...•
How do I reinstall grub in rhel8?
How to Reinstall Corrupted GRUB 2 on RHEL 8. To reinstall or recover the 'grub. cfg' file or 'grub2' directory you need to boot your system with the installation DVD/ISO image. On boot screen of Red Hat 8, Select the 'Troubleshooting' option and press enter.
How do I rebuild grub in RHEL 8?
Updating Grub boot loader on an RHEL or CentOS LinuxOpen the terminal app.Edit the /etc/default/grub as per your needs. For example: sudo vim /etc/default/grub.Type the following command as root user: sudo grub2-mkconfig -o /boot/grub2/grub.cfg.Reboot your Linux box. sudo reboot.
What is GRUB 2?
Grub 2 was a long awaited and very important upgrade over the previous version of the most popular and widely used boot manager in existence. Support for new filesystems, themes, improved splash capability, better internationalization, power-pc booting, dynamic module loading and scripting support. All this is great, but things can still go wrong and break unexpectedly. This basically means that a bootable partition (operating system) may become inaccessible and this is why Grub v2 offers a powerful rescue mode. Now using this mode, may not be exactly a walk in the park for most inexperienced users out there, so here's a guide on how to easily fix your Grub with the Boot Repair tool.
What is boot repair?
Boot Repair is a simplistic but powerful enough tool that promises to repair the most frequent problems that may arise on a Grub installation. The tool is usually not available through the default repositories of most distributions out there, so users will have to install it from 3rd party repositories. One example that contains the latest version of the software (there are many others too) is the yannubuntu ppa. Ubuntu/Mint/ElementaryOS users may install this tool by typing the following commands on a terminal:
How it looks?
There are basically three error messages or screens when GRUB fails to boot. grub>: This is the screen mode you see when GRUB has found everything except the configurationn file. This file probably will be grub.conf. grub rescue>: This is the mode when GRUB 2 is unable to find the GRUB folder or its contents are missing/corrupted.
Basic commands available
These are the commands that can be used when you enter the GRUB 2 terminl mode by pressing "c".
The Rescue Shell
If you get a rescue shell, this usually means that GRUB failed to load the "normal" module for some reason.
What is a GRUB?
GRUB or Grand Unified Bootloader is a bootloader package developed to allow users to select from two or more operating systems installed on a single disk. GRUB is what makes dual booting a PC with Windows and a Linux distribution such as Ubuntu possible. You can always install two operating systems on a disk but you’ll only be able ...
How does boot repair work?
Boot repair takes care of most of the other things that you would otherwise have to manually do via more complex commands. It also lets you copy the commands so you can simply paste them into the terminal and execute them easily.
Can you change the boot order of a Grub?
You can also change the boot order, so it would boot into your OS of choice by default unless you choose otherwise at the time of boot. GRUB can be edited using a tool called GRUB Customizer. To install it, just execute the following commands in a Terminal window.
Is the Grub still there?
GRUB is still there but the Windows bootloader takes preference over it, thus booting right into Windows. Today, we’ll see how to edit or repair GRUB boot menu.
Reinstall Ubuntu GRUB Boot Loader
1. After you’ve downloaded and burned the Ubuntu ISO image, or created a bootable USB stick, place the bootable media into your appropriate machine drive, reboot the machine and instruct the BIOS to boot into Ubuntu live image.
Manually Reinstall Ubuntu Grub Boot Loader
14.
How to repair GRUB?
To repair Grub, you may need to know the name of the boot and root partitions where Linux is installed. If you have many partitions on your disk you may not remember which one it is. You can run fsarchiver probe simple or fsarchiver probe detailed from SystemRescuecd to show the list of filesystems of your computer.
What is the root filesystem for Linux Debian?
There we can see that /dev/sda1 is the boot partition, and /dev/sda2 is the root filesystem for Linux-Debian. This is obvious because the labels are appropriate, but it’s not always that simple. All linux root filesystems are supposed to have their init program in /sbin/init.
Can you clone a partition?
disk cloning: you may want to clone your partitions to another disk or another computer for some reason. If you just clone the partitions of the disks, the sectors where Grub is installed may not be copied (eg: sectors before the first partition, or MBR).
Do I have to reinstall Linux?
Fortunately there are solutions to recover your linux installation by reinstalling Grub, and you don’t have to reinstall Linux entirely. All the administration programs required to re-enable Grub are part of the standard Linux installations, so the main problem is to access Linux the first time.
Can you boot a Linux system from a USB stick?
SystemRescueCd allows you to boot a Linux system installed on the disk even if grub is broken. You have to boot SystemRescueCd either from the cdrom, usb stick or the network . The purpose is to just have access to your system so that you can reinstall Grub from your original Linux installation.
How to Fix Grub After Windows 10 Upgrade
Post-Windows update, Microsoft overrides the Windows Boot Manager to use the NT bootloader. So, now when you restart your system, it directly boots up to Windows 10. This is because the Windows bootloader cannot identify Ubuntu. In order to enable booting to Ubuntu, we would need to make changes in the Windows boot registry.
Wrapping Up
These solutions should fix your problem. There are slim chances that they won’t and in that case, you would have to install a fresh copy of Ubuntu all over again.
GRUB Boot Issues
The most common reason for GRUB not booting into the operating system is another OS's bootloader overwriting GRUB boot configuration. The problem occurs during an attempt a dual boot with an existing Linux installation. Another reason is the accidental removal of GRUB configuration files.
GRUB Rescue Commands
Below is the list of the commonly used GRUB Rescue commands. Use the commands in the prompts mentioned in the previous section.
Fixing Boot Failure
This tutorial covers two ways to resolve GRUB boot issues, using the GRUB Rescue prompt, and the Boot Repair tool.
