Where has GRUB gone?

[melmerby]

Hi all

Notwithstanding my problems on my other computer with an invisible GRUB on 11.04, I have now lost GRUB completely on this computer using 10.04.
I haven't done any upgrades or software installs since I last used it but it now boots straight into Windows from the BIOS screens without a GRUB page at all!

Any suggestions?

Cheers
Keith

[dibl]

Re: Where has GRUB gone?

I have now lost GRUB completely on this computer using 10.04.

Grub doesn't just drop out of the back of your computer .... :P

However, setting aside the question of where it is hiding, you can reinstall it by following the applicable guidance here: http://kubuntuforums.net/forums/inde...opic=3117206.0

[melmerby]

Re: Where has GRUB gone?

Thank you dibl, there is plenty there to contemplate.

Keith

[dibl]

Re: Where has GRUB gone?

The part you need is this:

grub-install The most useful command

Full form: grub-install [OPTION] INSTALL_DEVICE

Two very important options are
--recheck
Probe a device map even if it already exists
--root-directory=DIR
Install GRUB images under the directory DIR instead of the root directory
(See discussion below.)

Examples:
INSTALL_DEVICE may be /dev/sda, /dev/sda1, hd0, hd1, etc.
grub-install /dev/sda installs GRUB 2 to the MBR of drive sda.
grub-install /dev/sda1 installs GRUB 2 to the boot sector of partition sda1.
grub-install hd0 installs GRUB 2 to the MBR of drive hd0.
grub-install --root-directory=/media/sdb1 /dev/sda
sets up GRUB 2 files in the mounted partition /media/sdb1
and then installs GRUB 2 to the MBR of drive sda using /media/sdb1/boot/grub files.
(If there is no /boot/grub directory in sdb1, it will be created and filled with GRUB 2 files.)
grub-install --recheck --root-directory=/media/sdb1 /dev/sda
Do it again, and probe the /boot/grub/device.map (again).

Use the command sudo grub-install for these purposes:
to refresh the entire GRUB 2 installation; or when you are re-installing GRUB 2 to fix a problem; or when you are installing GRUB 2 to another place or to a dedicated GRUB 2 partition or to a USB (flash) drive.

A master script
grub-install is a master script, called a utility, that invokes many other utilities (scripts) to help do its work. You issue this command at Konsole (Terminal) as root (using sudo). It does everything for you; it's a master fix-it-all command.

/usr/lib/grub/i386-pc
The master set of GRUB 2 files in your OS are kept in the GRUB 2 image directory /usr/lib/grub/i386-pc. They get there when you install GRUB 2 to your PC (or OS) using your package manager or using (sudo) apt-get install grub-pc.

grub-install does the following for you:

> The command sudo grub-install copies the GRUB 2 files from /usr/lib/grub/i386-pc to the directory /boot/grub. If /boot/grub does not yet exist, it is created.
> It probes your partition type and partitions (using grub-probe).
> It builds a custom version of core.img for your setup, one of two very important files (along with boot.img). (In GRUB LEGACY terms,, boot.img corresponds to stage_1 and core.img to stage_2.)
> Finally it installs GRUB 2 to your PC so it can boot some OS(s) for you. (It uses grub-setup to do this, setting boot.img in the MBR of your first BIOS boot drive and installs core.img either after the MBR or to a file system (e.g., your OS partition boot sector). See the note below for a few details.)

Two useful options
--recheck
Probe a device map even if it already exists
--root-directory=DIR
Install GRUB images under the directory DIR instead of the root directory

--recheck
If your grub-install command fails, complaining about a filesystem or not finding something, try it again with the option --recheck; like this example:
sudo grub-install --recheck --root-directory=/media/sdb1 /dev/sda

--root-directory=DIR
Very useful. Instead of setting up your GRUB files in /boot/grub under the root directory of your OS, you can use this option to build a /boot/grub directory anywhere, and then use those GRUB 2 files to install GRUB 2 to a hard drive MBR, or to a partition boot sector, or elsewhere (e.g., USB drive or dedicated GRUB 2 partition).
DIR is a directory, and so it is mounted. Thus, if using partition sdb1, for example, you must mount it, as say, /media/sdb1, and then it would be: --root-directory=/media/sdb1.

[melmerby]

Re: Where has GRUB gone?

How do I get into Kubuntu if I can't log on with GRUB?

Keith

[Qqmike]

Re: Where has GRUB gone?

See
SECTION 3 Fixing Things
Re-installing GRUB 2 using Live CD: Key Rescue Method

[melmerby]

Re: Where has GRUB gone?

OK cheers, I'll try that.

Keith

[buckeyered80]

Re: Where has GRUB gone?

I have had slight issues with Grub on 11.04 also. Mine also disappeared for a day. Believe it or not, it returned later on its own! LOL. It's been working since. Very strange. But I used 10.10 for about a year with no Grub issues.

[melmerby]

Re: Where has GRUB gone?

Decided to do a full install as there were one or two other issues that needed cleaning up.
Disaster. Kubuntu now boots up asking for a log-in and password. I don't use them for log-in!
I can't get into Kubuntu now.

Another re-install needed I think.

(Linux is a pain in the but at times)

Keith

[GreyGeek]

Re: Where has GRUB gone?

The Grub menu normally doesn't display on my 10.04 installation unless I hold down the Shift key from power-on until it pops up. IF you inadvertently changed your default OS to Windows you'd never see the grub menu as your system booted to WinX. Editing /etc/default/grub and making Kubuntu the default again, then running "update-grub" may be your fix. That's IF, of course, your grub didn't disappear off of your HD.

[melmerby]

Re: Where has GRUB gone?

The Grub menu normally doesn't display on my 10.04 installation unless I hold down the Shift key from power-on until it pops up. IF you inadvertently changed your default OS to Windows you'd never see the grub menu as your system booted to WinX. Editing /etc/default/grub and making Kubuntu the default again, then running "update-grub" may be your fix. That's IF, of course, your grub didn't disappear off of your HD.

I keep having various problems with Ubuntu/Kubuntu 10.04 on this machine and have re-installed many times to try and cure problems, which it normally does, but eventually something else will crop up and it will become unuseable. The OS is so unstable, its on a par with Windows 95 and that was bad!

This time I ended up with a log-in screen asking for username and password even though I had set automatic log-in and it wouldn't even accept the username and password I had set!
I re-installed again and it was great for about an hour then after a re-start I got a page full of text with errors such as no mount point, no such file etc.
I have given up on it and will stick with Windows XP which has run on this computer almost flawlessly for many years through several upgrades.

I have another PC where I was running 10.04 pretty reliably and did an upgrade to 11.04 and that also has a GRUB problem now (on another post) but at least it is still working.

Keith