Ошибка grub rescue no such device

Sometime you may encounter error messages like Error: no such device: xxxxx-xxxx-xxxx-xxxx-xxxxx  right after powering up the PC.

Such problems are caused by misconfigured GRUB, unable to load any operating system.

Usually happens when you resize, rename or shrink the disk partitions. Or may be even if you transfer a perfectly working hard drive from one PC to another.

But there’s an easy solution to deal with such problems, and here we’ll discuss about it.

Why this is happening?

This grub no such device problem usually happens when the boot drive’s UUID is changed somehow.

Like if you convert a disk drive with MBR partition table to GPT partition table. Another reason of UUID change is if you resize, merge, shrink or extend the linux root partition.

Here GRUB is present as bootloader, but it can’t find the proper modules and configuration file due to changed partition UUID.

To fix this problem, you’ve to determine three things.

First which one is the linux root( / ) partition, second how the system is booted, i.e. in UEFI mode or in legacy BIOS mode.

Third, if it’s booted in UEFI mode, then which is the EFI system partition?

You can use the parted command to determine the ESP partition, which is a FAT32 filesystem of around 100MB.

sudo parted /dev/sda print

Now the actual steps to fix the error no such device problem.

1. Use the ls command on the grub rescue prompt to list all the partitions.
2. Then you can use the ls command again to check the contents of each partitions to be sure.

   ls (hd0,1)/

   The linux root partition will contain /bin , /boot, /lib etc. etc directories.

3. If you’re sure about the linux root partition, then type the commands listed below one by one. In my case, the partition is (hd0,msdos5) .

   set root=(hd0,5)
   set prefix=(hd0,5)/boot/grub
   insmod normal
   normal

4. Then you should be able to access the GRUB boot menu like before, select the linux distro and boot to it.
5. After booting, you must be asked to login to your user account.
6. Next login to the account and open up a terminal window.
7. Then determine if the system is booted with UEFI mode or legacy BIOS mode, use the one liner script below.

   [ -d /sys/firmware/efi ] && echo "UEFI boot" || echo "Legacy boot"

8. To reinstall GRUB for legacy BIOS use this command.

   sudo grub-install /dev/sda --target=i386-pc

9. To re install GRUB on a UEFI based system, use this.

   sudo mount /dev/sda2 /boot/efi     # mount the EFI system partition
   sudo grub-install /dev/sda --target=x86_64-efi --efi-directory=esp

10. If grub installation reports no problem, then update the GRUB configuration file.

    sudo update-grub

11. Finally reboot the PC or laptop to check the if it worked at all or not.

Also don’t just copy-paste the commands, your EFI system partition could be different, most probably /dev/sda1 .

Conclusion

It’s not a very well described tutorial to fix the grub rescue no such device issue. But I hope you’ve got basic the idea to deal with the error no such device issue.

First you need to boot linux somehow then reinstall the GRUB bootloader and update the GRUB configuration. Here’s the detailed GRUB rescue tutorial.

If you’ve any question or suggestion, leave comments below.

5 апреля 2010 г.

GRUB

Ubuntu

Linux

Удалось мне немного поломать граб, из-за того что я удалил перед ним стоящий раздел с NTFS, ибо Windows мне уже не нужен. Что и следовало ожидать — появилась проблема:

error: unknown filesystem
grub rescue >

Решение

Вводим команду ls и наблюдаем следующее:

(hd0) (hd0,2) (hd0,3) (hd0,5) (hd0,6)

А теперь set:
prefix=(hd0,6)/boot/grub
root=(hd0,6)

Так как мы сместились на 1 раздел, то сетим на один меньше:
set prefix=(hd0,5)/boot/grub
set root=(hd0,5)

Теперь смотрим доступные моды и подгрузим необходимые нам:
ls /boot/grub
insmod /boot/grub/linux.mod
insmod /boot/grub/normal.mod



Моды можно подгружать и так:



  


                       
  




insmod normal

Теперь вбиваем команду normal и попадаем в меню загрузки граба:
normal

После того как вы попадете в систему, выполните:
sudo upgrade-from-grub-legacy

А вообще во всем этом мне помог https://help.ubuntu.com/community/Grub2 и особенно раздел «Rescue Mode».

I think I’ve exhausted all I know to do, so I’m sending up the flares. I’ll try to cover it all (albeit, in pieces), so please be patient.

I decided to install Linux Mint 11 where I previously had Ubuntu 10.10. Before this install, I had a partition with Windows XP, which—at some time in the distant past—I used to dual boot into. I removed the partition in this install.

After installation, the system fails to boot. After the check for a CD/DVD, it prints:

error: no such device: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
GRUB rescue>

There were no problems booting Ubuntu. I seem to recall a similar issue last time I did an install (instead of an upgrade) to Ubuntu. It’s been a while, but I thought I fixed it using FIXMBR and/or FIXBOOT from the XP CD. Those did not work this time.

The GRUB rescue> prompt seems to be broken. Even help doesn’t work. I am able to ls, which yields:

GRUB rescue> ls
(hd0) (hd0,msdos1) (hd1) (hd1,msdos1) (hd2) (hd2,msdos5) (hd2,msdos3) (hd2,msdos2) (hd2,msdos1)

Further, I don’t know what this device is. I can’t find a matching UUID under /dev/disk/by-uuid. For that matter, there are no UUIDs for my booting hard drive (sda, below). My setup is a Frankenbox. I know not to rely on device enumeration in such a mix, but they’re given below for easy discussion.

• Ch 0 Master: 250GB PATA (sda)
  • sda1
• Ch 0 Slave: none
• Ch 1 Master: 80GB SATA (sdb)
  • sdb1: /
  • sdb2: /home
  • sdb3: swap
• Ch 1 Slave: DVD SATA
• SATA expansion card: 250GB SATA (sdc)
  • sdc1

I thought I’d struck gold when I discovered some lingering (and confounding) RAID metadata on sda. The drive hadn’t shown up in the Linux install before, but did after using dmraid -r -E /dev/sda. However, the boot failure persisted.

Until just now, I could use the Mint install CD to «Boot from Local Drive», which would indeed take me to my installation on sdb1. After using the CD to boot to the drive, and running the below, I’ve worsened the problem to giving a GRUB> prompt instead of booting to the drive.

# GRUB-install --no-floppy /dev/sdb1
# update-GRUB
GRUB> find /boot/GRUB/stage1
GRUB> root (hd1,0) # result of above
GRUB> setup (hd0)

There’s definitely a mismatch, because sdb, which has 3 partitions, seems to be (hd2) at the GRUB rescue> prompt, but (hd1) when actually booted. However, if I’ve used UUIDs (and I think I have), this shouldn’t be a problem. Using the live CD, I see sdb1:/boot/GRUB/menu.list to contain

# kopt=root=UUID=[UUID of sdb1]
...
# groot=[UUID of sdb1]

The root problem, as I understand it, is that GRUB is, for some reason I don’t understand, trying to boot a device that doesn’t exist. I don’t know how to determine what it’s looking for by the UUID given. I don’t see any UUIDs for anything on sda.

And now, I can’t even boot to the drive using the CD.

Update:

I thought putting the /boot partition on the same drive as the MBR might help, so I added sda2, set the boot flag, and reinstalled (which is probably overkill).

I again get the grub rescue> prompt, but now, when I ls, I get

grub rescue> ls
(hd0) (hd0,msdos1) (hd1) (hd1,msdos2) (hd1,msdos1) (hd2) (hd2,msdos3) (hd2,msdos2) (hd2,msdos1)

So, sda is no more (hd0) at this prompt than sdb is (hd1). I don’t know why it’s so misaligned, nor why it matters. I may try again, putting /boot on sdc/(hd0).

Hi bcbc, thanks for your help.

These are the results of the bootinfoscript:

Boot Info Script 0.60 from 17 May 2011

============================= Boot Info Summary: ===============================

=> Syslinux MBR (4.04 and higher) is installed in the MBR of /dev/sdc.
=> Grub2 (v1.99) is installed in the MBR of /dev/mapper/isw_dffiejdfai_ARRAY1
and looks at sector 1 of the same hard drive for core.img. core.img is at
this location and looks in partition 5 for /boot/grub.

sdc1: __________________________________________________ ________________________

File system: vfat
Boot sector type: SYSLINUX 4.04 2011-04-18
Boot sector info: Syslinux looks at sector 2112440 of /dev/sdc1 for its
second stage. SYSLINUX is installed in the directory.
The integrity check of the ADV area failed. No errors
found in the Boot Parameter Block.
Operating System:
Boot files: /boot/grub/grub.cfg /syslinux/syslinux.cfg /ldlinux.sys

isw_dffiejdfai_ARRAY11: __________________________________________________ ______

File system:
Boot sector type: Unknown
Boot sector info:
Mounting failed: mount: unknown filesystem type »

isw_dffiejdfai_ARRAY12: __________________________________________________ ______

File system:
Boot sector type: Unknown
Boot sector info:
Mounting failed: mount: unknown filesystem type »
mount: unknown filesystem type »

isw_dffiejdfai_ARRAY13: __________________________________________________ ______

File system:
Boot sector type: Unknown
Boot sector info:
Mounting failed: mount: unknown filesystem type »
mount: unknown filesystem type »
mount: unknown filesystem type »

============================ Drive/Partition Info: =============================

Drive: sdc __________________________________________________ ___________________

Disk /dev/sdc: 16.0 GB, 16001036288 bytes
32 heads, 63 sectors/track, 15501 cylinders, total 31252024 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes

Partition Boot Start Sector End Sector # of Sectors Id System

/dev/sdc1 * 63 31,250,015 31,249,953 b W95 FAT32

Drive: isw_dffiejdfai_ARRAY1 __________________________________________________ ___________________

Disk /dev/mapper/isw_dffiejdfai_ARRAY1: 2000.4 GB, 2000405397504 bytes
255 heads, 63 sectors/track, 243202 cylinders, total 3907041792 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes

Partition Boot Start Sector End Sector # of Sectors Id System

/dev/mapper/isw_dffiejdfai_ARRAY11 63 80,324 80,262 de Dell Utility
/dev/mapper/isw_dffiejdfai_ARRAY12 * 81,920 27,865,087 27,783,168 7 NTFS / exFAT / HPFS
/dev/mapper/isw_dffiejdfai_ARRAY13 27,865,088 3,702,237,183 3,674,372,096 7 NTFS / exFAT / HPFS

«blkid» output: __________________________________________________ ______________

Device UUID TYPE LABEL

/dev/loop0 squashfs
/dev/mapper/isw_dffiejdfai_ARRAY1p1 5450-4444 vfat DellUtility
/dev/mapper/isw_dffiejdfai_ARRAY1p2 82DA4512DA4503BF ntfs RECOVERY
/dev/mapper/isw_dffiejdfai_ARRAY1p3 D4F84A64F84A44C8 ntfs OS
/dev/sda isw_raid_member
/dev/sdb isw_raid_member
/dev/sdc1 64ED-5B1A vfat PENDRIVE

========================= «ls -R /dev/mapper/» output: =========================

/dev/mapper:
control
isw_dffiejdfai_ARRAY1
isw_dffiejdfai_ARRAY1p1
isw_dffiejdfai_ARRAY1p2
isw_dffiejdfai_ARRAY1p3

================================ Mount points: =================================

Device Mount_Point Type Options

/dev/loop0 /rofs squashfs (ro,noatime)
/dev/sdc1 /cdrom vfat (ro,relatime,fmask=0022,dmask=0022,codepage=cp437, iocharset=iso8859-1,shortname=mixed,errors=remount-ro)

=========================== sdc1/boot/grub/grub.cfg: ===========================

———————————————————————————

if loadfont /boot/grub/font.pf2 ; then
set gfxmode=auto
insmod efi_gop
insmod efi_uga
insmod gfxterm
terminal_output gfxterm
fi

set menu_color_normal=white/black
set menu_color_highlight=black/light-gray

menuentry «Try Ubuntu without installing» {
set gfxpayload=keep
linux /casper/vmlinuz file=/cdrom/preseed/ubuntu.seed boot=casper quiet splash —
initrd /casper/initrd.lz
}
menuentry «Install Ubuntu» {
set gfxpayload=keep
linux /casper/vmlinuz file=/cdrom/preseed/ubuntu.seed boot=casper only-ubiquity quiet splash —
initrd /casper/initrd.lz
}
menuentry «Check disc for defects» {
set gfxpayload=keep
linux /casper/vmlinuz boot=casper integrity-check quiet splash —
initrd /casper/initrd.lz
}
———————————————————————————

========================= sdc1/syslinux/syslinux.cfg: ==========================

———————————————————————————
# D-I config version 2.0
include menu.cfg
default vesamenu.c32
prompt 0
timeout 50

# If you would like to use the new menu and be presented with the option to install or run from USB at startup, remove # from the following line. This line was commented out (by request of many) to allow the old menu to be presented and to enable booting straight into the Live Environment!
# ui gfxboot bootlogo
———————————————————————————

=================== sdc1: Location of files loaded by Grub: ====================

GiB — GB File Fragment(s)

?? = ?? boot/grub/grub.cfg 1

================= sdc1: Location of files loaded by Syslinux: ==================

GiB — GB File Fragment(s)

?? = ?? ldlinux.sys 1
?? = ?? syslinux/gfxboot.c32 1
?? = ?? syslinux/syslinux.cfg 1
?? = ?? syslinux/vesamenu.c32 1

============== sdc1: Version of COM32(R) files used by Syslinux: ===============

syslinux/gfxboot.c32 : COM32R module (v4.xx)
syslinux/vesamenu.c32 : COM32R module (v4.xx)

======================== Unknown MBRs/Boot Sectors/etc: ========================

Unknown BootLoader on isw_dffiejdfai_ARRAY11

Unknown BootLoader on isw_dffiejdfai_ARRAY12

Unknown BootLoader on isw_dffiejdfai_ARRAY13

========= Devices which don’t seem to have a corresponding hard drive: =========

sdd sde sdf sdg

=============================== StdErr Messages: ===============================

unlzma: Decoder error
/home/ubuntu/Desktop/boot_info_script.sh: line 1579: [: 2.73495e+09: integer expression expected
hexdump: /dev/mapper/isw_dffiejdfai_ARRAY11: No such file or directory
hexdump: /dev/mapper/isw_dffiejdfai_ARRAY11: No such file or directory
hexdump: /dev/mapper/isw_dffiejdfai_ARRAY12: No such file or directory
hexdump: /dev/mapper/isw_dffiejdfai_ARRAY12: No such file or directory
hexdump: /dev/mapper/isw_dffiejdfai_ARRAY13: No such file or directory
hexdump: /dev/mapper/isw_dffiejdfai_ARRAY13: No such file or directory

I have got a machine with Windows and Linux Mint. Now that I needed to upgrade my Mint because I needed the new fixes, I cannot boot. I get the error message no such device, grub rescue. My guess is that the disk id has been changed and grub cannot find it. I do not remember where I originally installed the grub. The output from fdisk:

Disk /dev/sda: 256.1 GB, 256060514304 bytes
255 heads, 63 sectors/track, 31130 cylinders, total 500118192 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x5e24ae5b

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048      206847      102400    7  HPFS/NTFS/exFAT
/dev/sda2          206848   500115455   249954304    7  HPFS/NTFS/exFAT

Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x5e24ae82

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *        2048   929521663   464759808    7  HPFS/NTFS/exFAT
/dev/sdb2       929523710  1953523711   512000001    5  Extended
Partition 2 does not start on physical sector boundary.
/dev/sdb5       929523712  1887181915   478829102   83  Linux
/dev/sdb6      1887184896  1953523711    33169408   82  Linux swap / Solaris

I have searched the forums and ran the grub-install on /dev/sdb1. Still getting the same error. However, during startup when I change the boot disk to the second one (/dev/sdb1), I am able to boot, and even to the old Windows I had. My yet another guess is that if I do grub-install on /dev/sda1, it will fix my problem, but I am hesitating doing so because I cannot and must not lose data on that partition.

So, my question is: Is it safe to do grub-install /dev/sda? How do I check if the old grub was installed there, the one that is not able to boot?

Grub представляет собой универсальный загрузчик для Linux и других ОС. Например, с его помощью пользователь может иметь несколько операционных систем на одном компьютере, выбирая при включении нужную систему для загрузки. Но в некоторых случаях пользователь сталкивается с ошибкой Grub Rescue Unknown Filesystem.

Почему возникает эта ошибка?

Причины разные: например, загрузочные файлы отсутствуют либо они были перемещены. Кроме того, метрики раздела /boot могли быть изменены либо этот раздел был отформатирован, то есть он больше не существует.

Прежде всего, надо понимать, что Grub инсталлируется в 2 места. Одно из них — таблица разделов MBR. Тут места немного, поэтому весь загрузчик сюда не помещается. Однако он обладает модульной структурой, то есть все основные модули, ресурсы и конфигурационные файлы размещаются на обычном разделе (монтируется после загрузки в /boot). При этом программа в MBR «помнит», в каком месте располагается раздел /boot, однако если с данным разделом что-либо произойдет, то программа не загрузит привычные модули, следовательно, появится ошибка unknown filesystem. Значит все это следующее: если раздел уже не существует, остается лишь брать LiveCD диск и выполнять переустановку загрузчика. Если же раздел просто изменен, то есть возможность исправить ситуацию.

Как исправить?

Прежде всего, воспользуйтесь командой ls, чтобы узнать список доступных разделов:

Далее просмотрите содержимое каждого раздела — это позволит понять, где именно располагаются файлы модулей, пример:

Если увидели папку boot, то это нужный раздел. Далее инсталлируем данный раздел значением переменной root и посредством команды set:

set prefix=(hd0,1)/boot/grub


Потом загружаем и запускаем модуль normal — он загрузит все, что необходимо:



Если раздел /boot поврежден не был, загрузчик корректно определит все файлы и запустит привычное меню. Конечно же, после загрузки надо будет восстановить загрузчик Grub для того, чтобы не вводить вышеописанные команды при каждой загрузке ОС. Если же вышерассмотренным способом проблему решить не удастся, придется пройти процедуру переустановки загрузчика с помощью LiveCD-диска.
По материалам блога https://losst.ru/.

5 апреля 2010 г.

GRUB

Ubuntu

Linux

Удалось мне немного поломать граб, из-за того что я удалил перед ним стоящий раздел с NTFS, ибо Windows мне уже не нужен. Что и следовало ожидать — появилась проблема:

error: unknown filesystem
grub rescue >

Решение

Вводим команду ls и наблюдаем следующее:

(hd0) (hd0,2) (hd0,3) (hd0,5) (hd0,6)

А теперь set:
prefix=(hd0,6)/boot/grub
root=(hd0,6)

Так как мы сместились на 1 раздел, то сетим на один меньше:
set prefix=(hd0,5)/boot/grub
set root=(hd0,5)

Теперь смотрим доступные моды и подгрузим необходимые нам:
ls /boot/grub
insmod /boot/grub/linux.mod
insmod /boot/grub/normal.mod


Моды можно подгружать и так:
insmod normal

Теперь вбиваем команду normal и попадаем в меню загрузки граба:
normal

После того как вы попадете в систему, выполните:
sudo upgrade-from-grub-legacy

А вообще во всем этом мне помог https://help.ubuntu.com/community/Grub2 и особенно раздел «Rescue Mode».