HOWTO: Boot & Install Ubuntu from the Grub Rescue Prompt

[volinkov]

I ran the boot repair, and it updated the grub modules on my hard drive, which I confirmed. I then went to boot from the hard drive, but I am still having the same problem with grub rescue.

Using the "ls" command, it returns (hd0) (hd0,msdos1)
The second one is my external drive.
Using ls (hd0,msdos1)/ returns all of the directories and files in the home directory. Awesome.
Next, when I try to use "ls (hd0,msdos1)/boot/grub/" ,which is where the grub directory and modules are , it returns "error:file not found". If I just use "ls (hd0,msdos1)/boot/" it doesn't error, but it also doesn't return any of the files/directories that I know are in there.

Is my grub broken?

Also, I got the results.txt file:

Boot Info Script 0.60 from 17 May 2011


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

=> Grub2 (v1.99) is installed in the MBR of /dev/sda and looks at sector 1 of
the same hard drive for core.img. core.img is at this location and looks
for on this drive.

sda1: __________________________________________________ ________________________

File system: ext4
Boot sector type: -
Boot sector info:
Operating System: Ubuntu 11.10
Boot files: /boot/grub/grub.cfg /etc/fstab /boot/grub/core.img

sda2: __________________________________________________ ________________________

File system: Extended Partition
Boot sector type: -
Boot sector info:

sda5: __________________________________________________ ________________________

File system: swap
Boot sector type: -
Boot sector info:

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

Drive: sda __________________________________________________ ___________________

Disk /dev/sda: 500.1 GB, 500107859968 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773164 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/sda1 * 2,048 968,452,095 968,450,048 83 Linux
/dev/sda2 968,454,142 976,771,071 8,316,930 5 Extended
/dev/sda5 968,454,144 976,771,071 8,316,928 82 Linux swap / Solaris


"blkid" output: __________________________________________________ ______________

Device UUID TYPE LABEL

/dev/loop0 squashfs
/dev/sda1 c115a6e2-5b2a-4b13-a810-6373cec0e25e ext4
/dev/sda5 b39b8a64-11c5-48f4-a44e-c507334989a1 swap

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

Device Mount_Point Type Options

/dev/loop0 /rofs squashfs (ro,noatime)
/dev/sr0 /cdrom iso9660 (ro,noatime)


=========================== sda1/boot/grub/grub.cfg: ===========================

--------------------------------------------------------------------------------
#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
if [ -s $prefix/grubenv ]; then
set have_grubenv=true
load_env
fi
set default="0"
if [ "${prev_saved_entry}" ]; then
set saved_entry="${prev_saved_entry}"
save_env saved_entry
set prev_saved_entry=
save_env prev_saved_entry
set boot_once=true
fi

function savedefault {
if [ -z "${boot_once}" ]; then
saved_entry="${chosen}"
save_env saved_entry
fi
}

function recordfail {
set recordfail=1
if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi
}

function load_video {
insmod vbe
insmod vga
insmod video_bochs
insmod video_cirrus
}

insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set=root c115a6e2-5b2a-4b13-a810-6373cec0e25e
if loadfont /usr/share/grub/unicode.pf2 ; then
set gfxmode=auto
load_video
insmod gfxterm
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set=root c115a6e2-5b2a-4b13-a810-6373cec0e25e
set locale_dir=($root)/boot/grub/locale
set lang=en_US
insmod gettext
fi
terminal_output gfxterm
if [ "${recordfail}" = 1 ]; then
set timeout=10
else
set timeout=10
fi
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/05_debian_theme ###
set menu_color_normal=white/black
set menu_color_highlight=black/light-gray
if background_color 44,0,30; then
clear
fi
### END /etc/grub.d/05_debian_theme ###

### BEGIN /etc/grub.d/10_linux ###
if [ ${recordfail} != 1 ]; then
if [ -e ${prefix}/gfxblacklist.txt ]; then
if hwmatch ${prefix}/gfxblacklist.txt 3; then
if [ ${match} = 0 ]; then
set linux_gfx_mode=keep
else
set linux_gfx_mode=text
fi
else
set linux_gfx_mode=text
fi
else
set linux_gfx_mode=keep
fi
else
set linux_gfx_mode=text
fi
export linux_gfx_mode
if [ "$linux_gfx_mode" != "text" ]; then load_video; fi
menuentry 'Ubuntu, with Linux 3.0.0-12-generic-pae' --class ubuntu --class gnu-linux --class gnu --class os {
recordfail
set gfxpayload=$linux_gfx_mode
insmod gzio
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set=root c115a6e2-5b2a-4b13-a810-6373cec0e25e
linux /boot/vmlinuz-3.0.0-12-generic-pae root=UUID=c115a6e2-5b2a-4b13-a810-6373cec0e25e ro quiet splash vt.handoff=7
initrd /boot/initrd.img-3.0.0-12-generic-pae
}
menuentry 'Ubuntu, with Linux 3.0.0-12-generic-pae (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os {
recordfail
insmod gzio
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set=root c115a6e2-5b2a-4b13-a810-6373cec0e25e
echo 'Loading Linux 3.0.0-12-generic-pae ...'
linux /boot/vmlinuz-3.0.0-12-generic-pae root=UUID=c115a6e2-5b2a-4b13-a810-6373cec0e25e ro recovery nomodeset
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-3.0.0-12-generic-pae
}
submenu "Previous Linux versions" {
menuentry 'Ubuntu, with Linux 3.0.0-12-generic' --class ubuntu --class gnu-linux --class gnu --class os {
recordfail
set gfxpayload=$linux_gfx_mode
insmod gzio
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set=root c115a6e2-5b2a-4b13-a810-6373cec0e25e
linux /boot/vmlinuz-3.0.0-12-generic root=UUID=c115a6e2-5b2a-4b13-a810-6373cec0e25e ro quiet splash vt.handoff=7
initrd /boot/initrd.img-3.0.0-12-generic
}
menuentry 'Ubuntu, with Linux 3.0.0-12-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os {
recordfail
insmod gzio
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set=root c115a6e2-5b2a-4b13-a810-6373cec0e25e
echo 'Loading Linux 3.0.0-12-generic ...'
linux /boot/vmlinuz-3.0.0-12-generic root=UUID=c115a6e2-5b2a-4b13-a810-6373cec0e25e ro recovery nomodeset
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-3.0.0-12-generic
}
}
### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/20_memtest86+ ###
menuentry "Memory test (memtest86+)" {
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set=root c115a6e2-5b2a-4b13-a810-6373cec0e25e
linux16 /boot/memtest86+.bin
}
menuentry "Memory test (memtest86+, serial console 115200)" {
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set=root c115a6e2-5b2a-4b13-a810-6373cec0e25e
linux16 /boot/memtest86+.bin console=ttyS0,115200n8
}
### END /etc/grub.d/20_memtest86+ ###

### BEGIN /etc/grub.d/30_os-prober ###
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries. Simply type the
# menu entries you want to add after this comment. Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###

### BEGIN /etc/grub.d/41_custom ###
if [ -f $prefix/custom.cfg ]; then
source $prefix/custom.cfg;
fi
### END /etc/grub.d/41_custom ###
--------------------------------------------------------------------------------

=============================== sda1/etc/fstab: ================================

--------------------------------------------------------------------------------
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
proc /proc proc nodev,noexec,nosuid 0 0
# / was on /dev/sda1 during installation
UUID=c115a6e2-5b2a-4b13-a810-6373cec0e25e / ext4 errors=remount-ro 0 1
# swap was on /dev/sda5 during installation
UUID=b39b8a64-11c5-48f4-a44e-c507334989a1 none swap sw 0 0
--------------------------------------------------------------------------------

=================== sda1: Location of files loaded by Grub: ====================

GiB - GB File Fragment(s)

376.131866455 = 403.868516352 boot/grub/core.img 1
356.174201965 = 382.439137280 boot/grub/grub.cfg 1
1.427730560 = 1.533014016 boot/initrd.img-3.0.0-12-generic 1
1.005863190 = 1.080037376 boot/initrd.img-3.0.0-12-generic-pae 2
356.172374725 = 382.437175296 boot/vmlinuz-3.0.0-12-generic 1
0.700729370 = 0.752402432 boot/vmlinuz-3.0.0-12-generic-pae 2
1.427730560 = 1.533014016 initrd.img 1
356.172374725 = 382.437175296 vmlinuz 1

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

unlzma: Decoder error

[drs305]

volinkov,

The problem most likely is that your Grub files are located on a portion of the drive which can't be seen by BIOS or Grub 2. On many BIOS there is a 137GB limitation on what the BIOS can see. Your Grub 2 files are beyond that limit.

You can check by booting and entering the BIOS setup. Check the reported disk size. If it reports approximately 137 GB, that is the problem. If there is a setting to enable large drives or LBA, enable it. You might also be able to update the BIOS.

If your setup will allow it, shrinking your sda1 partition to approximately 130GB will probably also fix the problem, since it will force the Grub 2 files to be placed within the 137GB limit. If you have to shrink the partition, you will need to use the LiveCD or another 'rescue' type CD since your Ubuntu partition must be unmounted. Gparted is an excellent tool for resizing linux partitions.

The usual caution about backing up critical data files whenever performing partitioning operations.

[volinkov]

I resized the partition and she booted up just fine. Thanks for your help!

[brewmasterkyle]

Help!

I've found that my linux partition is (hd1,1)

I've also found that my grub modules are in (hd1,1)/usr/lib/grub/i386-pc

I then typed

set prefix=(hd1,1)/usr/lib/grub/i386-pc
insmod linux

At which point, it gives me the error:

error: symbol not found: 'grub-mm-base'.

I don't know what to do from here. Please help!!

[drs305]

I've found that my linux partition is (hd1,1)

I've also found that my grub modules are in (hd1,1)/usr/lib/grub/i386-pc

I then typed

set prefix=(hd1,1)/usr/lib/grub/i386-pc
insmod linux

At which point, it gives me the error:

Good for you for being able to locate the modules.

Where you found them is where the originals are stored, but they are the source and are transferred to the boot folder during installation. You might be able to copy them to your /boot/grub folder. I don't know if the installation process does anything more than a direct copy regarding the modules.


You can use the LiveCD to try a direct copy to the mounted grub folder. However, if you use a LiveCD I'd recommend chrooting into your Ubuntu partition and reinstalling Grub 2 completely. I suspect that would be more reliable unless your only problem is missing modules, and nothing else. That is covered in the "Chroot" link in my signature line.

If the modules exist in hd1,1/boot/grub, you can try manually booting with these commands:

ls (hd1,1)/boot/grub 
# Do you see the modules? If not, try the alternate module loading command later.
set prefix=(hd1,1)/boot/grub
set root=(hd1,1)
insmod (hd1,1)/boot/grub/linux.mod
# Alternate module load:
# insmod (hd1,1)/usr/lib/grub/i386-pc/linux.mod
# Other modules may be needed as well. Watch for errors when you try to boot.
linux (hd1,1)/vmlinuz root=/dev/sdb1 ro
initrd (hd1,1)/initrd.img
boot

[sprintexec]

'out of disk' can be caused by many things. Often it means the BIOS cannot read the drive. You should probably open up your BIOS setup during boot and check the reported drive size. If the BIOS does not report the full size of your drive, any files physically located beyond the limit seen by the BIOS will not be found.

This little snippet of information was all that I needed to find to get my otherwise no-starting 11.10 installation to boot. I had wondered how it could be that the CD would run perfectly but yet the full install did not.

Thank you DRS305

[drs305]

This little snippet of information was all that I needed to find to get my otherwise no-starting 11.10 installation to boot. I had wondered how it could be that the CD would run perfectly but yet the full install did not.

Thank you DRS305

You are most welcome.

This issue comes up fairly often, especially on older systems.

Even with today's larger drive sizes some relatively recent BIOS's still have the 137GB limit built into them. Presumably because the manufacturers believe that users will only have one OS installed on their computers and the boot files will be very early on the disk.

[c.cobb]

Hi drs305,
I was just going through your nice HowTo making some crib notes when I noticed that you could save a step (and some typing) by omitting the 'iso-scan/filename=' kernel parameter. Without this, the /isodevice directory does not get mounted, and you are left with just the read-only /cdrom mount point -- at least this is how it works when booting 10.04.

Also, for times when you do include the 'iso-scan' param, the file you select can be any existing file on the drive; it doesn't have to be the ISO. A while back I dug down into the lupin-casper shell scripts to see how it worked, because I wanted to have /isodevice mounted when not booting from an ISO file -- again this is on 10.04, so hope it hasn't changed.
Solo mis dos centavos,

[drs305]

Hi drs305,
I was just going through your nice HowTo making some crib notes when I noticed that you could save a step (and some typing) by omitting the 'iso-scan/filename=' kernel parameter. Without this, the /isodevice directory does not get mounted, and you are left with just the read-only /cdrom mount point -- at least this is how it works when booting 10.04.

Also, for times when you do include the 'iso-scan' param, the file you select can be any existing file on the drive; it doesn't have to be the ISO. A while back I dug down into the lupin-casper shell scripts to see how it worked, because I wanted to have /isodevice mounted when not booting from an ISO file -- again this is on 10.04, so hope it hasn't changed.
Solo mis dos centavos,

I appreciate the input.

I've been swamped lately but I'll try to test this in my other releases and update the file.

We struggled with how to set this up before there was any documentation and there are some pretty amusing posts by a group of us scattered around these forums as we tested various ideas. While we got it working, as you discovered there very well can be other and better ways of doing things.

In the meantime, happy holidays and thanks again.

[c.cobb]

Yes, I've followed several of your threads on Grub2, and they've all been very helpful. By coincidence I had a chance to confirm that lupin-casper on Natty still works the same way.

After posting here last night, I tried another of your suggestions to update Grub2 on a 10.04 install and, in addition to the three packages you mention, it also happened to update lupin-casper. So, this morning I went poking around and, while things have changed some (iirc), the 'iso-scan' mount part works the same.

Thanks and happy holidays to you as well.
Cheers,

p.d. For Natty the pertinent parts are in these two scripts.

/usr/share/initramfs-tools/scripts/casper-premount/20iso_scan
/usr/share/initramfs-tools/scripts/lupin-helpers