grub rescue prompt

G-Raps · 05-28-2020, 06:24 AM

Hi All,

While I have a working system, I would like to draw attention to a situation that some of you may have experienced at one point or another. When the partitions of a disk fail for some reason or other, the Linux grub rescue prompt appears on the screen. Some descriptions that show onscreen describe that one has started up the system from a crash, and then the prompt appears, like the following:

grub rescue>

Some options for this prompt include ls, ?, help, and some system commands like mount, df, and lsusb. What are some tips useful for analyzing the system and restoring to a working boot of an operating system ?

yancek · 05-28-2020, 07:22 AM

You should be able to find a number of sites similar to the one below with an online search with 'how to boot from a grub prompt.

https://help.ubuntu.com/community/Grub2/Troubleshooting

hazel · 05-28-2020, 10:59 AM

Usually when you get the grub prompt, grub has failed to find the kernel or one of the other files it has been told to load. However the grub shell is running and you can seek out and load these files by hand.

When you get the grub rescue prompt, it means that grub has failed to find the grub shell itself. The shell is one of the grub modules, so there may be something wrong with your grub install or with the /boot directory.

beachboy2 · 05-28-2020, 01:29 PM

G-Raps,

Have a copy of Boot-Repair-Disk or Rescatux handy on a DVD or USB drive:

https://sourceforge.net/p/boot-repair-cd/home/Home/

https://www.supergrubdisk.org/

G-Raps · 05-31-2020, 09:46 AM

Thanks for the somewhat dated Rescatux and Super Grub 2 disk ISO images. However, they seem dated for purposes of rescuing a virtual machine instance, right ? I have a Dreamhost virtual machine instance (cloud server) that is running Debian 7. When I have to maintain the server, I use the Dreamhost dashboard web interface to tap into the server and log in as a localhost. However, there is no native console display on this virtual machine. Which makes using the Rescatux and Super Grub 2 disk images challenging in a command-line interface.

Is there a more recent command-line, console authenticated version ?

shruggy · 05-31-2020, 10:41 AM

A good command-line rescue LiveCD for Debian would be Grml. This is from my /boot/grub/grub.cfg, created by update-grml-rescueboot:

Code:

menuentry "Grml Rescue System (grml64-small_2018.12.iso)" {
        insmod part_msdos
        insmod ext2
        set root='hd0,msdos1'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremetal=ahci0,msdos1  b22ffd66-807d-4a06-bfc6-3c5c975b57fd
        else
          search --no-floppy --fs-uuid --set=root b22ffd66-807d-4a06-bfc6-3c5c975b57fd
        fi
        iso_path="/grml/grml64-small_2018.12.iso"
        export iso_path
        kernelopts="   "
        export kernelopts
        loopback loop "/grml/grml64-small_2018.12.iso"
        set root=(loop)
        configfile /boot/grub/loopback.cfg
}

colorpurple21859 · 05-31-2020, 09:46 PM

.

Quote:

When the partitions of a disk fail for some reason or other, the Linux grub rescue prompt appears on the screen.

If it was your root partition or boot partition if /boot is separate, you want recover from the grub-rescue prompt, you will need a live iso or reinstall.
Do you know what the failure is?
Here is another how-to to recover from grub-rescue prompt if it is possible.
https://www.howtoforge.com/tutorial/...h-grub-rescue/