Posts tagged ‘grub’

[howto] Enable/Disable GRUB Password

NOTE: This is not a rock solid secured way of disabling access to your pc. But atleast for those “Windoze users” who have no clue wtf is a grub, it’s going to be pretty effective! I’m going to teach you how to enable as well as disable grub password.

Enable GRUB password:

1. Open terminal and type as root:

# cp /boot/grub/menu.lst /boot/grub/menu.lst.backup

2. Now that your GRUB is backed up. Type:

# grub

grub> md5crypt

Password: ******** [Type in the password that you want to encrypt!]

Now copy the encrypted message it gives you!

grub> quit

3. Open /boot/grub/menu.lst.backup and paste the message after initrd line. If you have a number of Grub entries , you must paste it [or use a different encrypted password using the above method] for every entry that you want to password protect! Use it like this:

title           Debian GNU/Linux, squeeze/sid
root            (hd0,1)
kernel          /boot/vmlinuz-2.6.30-1-amd64 root=/dev/hda2 ro splash quiet vga=791
initrd          /boot/initrd.img-2.6.30-1-amd64

password – -md5 gasgd6876b2dsd2d/

paste the code after “password – -md5”

Note: Since wordpress has the weird habit of showing double hyphen as a single large one, I put a space in between the two, you just need to put two hyphens without any space in between!

Disable/Hack GRUB password:

1. You need a Linux live CD for this.

2. Insert the CD and boot from it.

3. In command line [or if you’re using ubuntu cd 😛 open a terminal and type]:

$ su

# fdisk -l [to check the name of the root directory]

# mount -t ext3 -o rw /dev/sda2 /mnt

[change ext3 to ext4 and /dev/sda2 according o the fdisk -l output]

# chroot /mnt /bin/bash

# nano /boot/grub/menu.lst

Now just remove the password line from the grub menu. 😛 Simple eh? Now save , unmount the partition and reboot!

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[howto] Restore Grub

It is always recommended to install Windows first and then Linux, however if you would prefer [for some weird reasons] to do the opposite then follow this guide!

Requirement:

You need a Linux LIVE CD. E.g.-> ubuntu or suse or mandriva,etc etc.

Boot from your Live CD. Now open a terminal and type in:

grub

find /boot/grub/stage1

Now it will show you the correct root partition.

root (hd0,1)   [replace 0 and 1 according to the output!]

setup (hd0)

quit

sudo grub-install /dev/sda [or hda , whichever is your MBR]

reboot

Done!

[Out-dated] GRUB-GFX {Graphical Grub Menu}

GRUB-GFX will transform your ugly grub menu into a beautiful one.

First remove your older grub:

apt-get remove grub

Download the 32bit version from here. I use 64bit, but it’s not available anywhere it seems so I might upload it somewhere if someone requests!

Goto the folder where you downloaded it and install using

dpkg -i filename.deb

Download the suse grub from here. Put it in a new folder else it will get messy!

cpio -i < message.suse

This will extract it! See toldya’ it will get messy!

Now edit the pictures as you want and then put it back up:

ls . |cpio -o > /boot/grub/message.custom

If you don’t want to go through this hassle there are countless themes already there, search in Gnome-look.org or KDE-look.org. For debian users you can try out this one.

Just copy it into /boot/grub

cp mesage.debianorange /boot/grub/

Then edit your menu.lst

Code:
sudo cp /boot/grub/menu.lst /boot/grub/menu.lst_backup
sudo gedit /boot/grub/menu.lst

and make it use gfxboot

Code:
gfxmenu /boot/grub/message.suse # the suse can be replaced

Type in:

grub
grub> find /boot/grub/stage1
(hdx,y) # this will be the output
grub> root (hdx,y)
grub> setup (hdx)

Replace hdx,y with whatever output it shows, for me it was (hd0,1)

Now :

grub-install /dev/hda [or sda whichever is your MBR]

update-grub

Reboot and enjoy!

NOTE: Please follow this guide if you run into any problem.

GRUB 2 [howto]

Click to enlarge

Click to enlarge

GRUB 2

GRUB 2 is derived from PUPA which was a research project to investigate the next generation of GRUB. GRUB 2 has been rewritten from scratch to clean up everything for modularity and portability. A mailing list and a wiki have been setup for discussing the development of GRUB 2.

GRUB 2 targets at the following goals:

  • Scripting support, such as conditionals, loops, variables and functions.
  • Graphical interface.
  • Dynamic loading of modules in order to extend itself at the run time rather than at the build time.
  • Portability for various architectures.
  • Internationalization. This includes support for non-ASCII character code, message catalogs like gettext, fonts, graphics console, and so on.
  • Real memory management, to make GNU GRUB more extensible.
  • Modular, hierarchical, object-oriented framework for file systems, files, devices, drives, terminals, commands, partition tables and OS loaders.
  • Cross-platform installation which allows for installing GRUB from a different architecture.
  • Rescue mode saves unbootable cases. Stage 1.5 was eliminated.
  • Fix design mistakes in GRUB Legacy, which could not be solved for backward-compatibility, such as the way of numbering partitions.

Multiboot Specification

Multiboot Specification is a protocol between a boot loader and an OS kernel. Because this specification is generic, you can use the protocol in your own boot loader and/or in your own OS freely. Follow this link, for more details.

Howto Install Grub2 in Debian and Ubuntu?

Here goes.

First remove your grub.

apt-get remove grub

apt-get install grub2 grub2-splashimages

The new GRUB2 splash images are installed at:

# ls /usr/share/images/grub/

Once you’ve rebooted, your default grub will load up and it has a new option called ‘Chainload into Grub 2′.When you are satisfied that GRUB2 works then you can select the second option, “upgrade-from-grub-legacy

You change the grub images from:

/usr/share/images/grub/

# nano /etc/grub.d/05_debian_theme

and change the following line from:

for i in {/boot/grub,/usr/share/images/desktop-base}/moreblue-orbit-grub.{png,tga}
to
for i in {/boot/grub,/usr/share/images/desktop-base,/usr/share/images/grub}/Plasma-lamp.{png,tga} and save the file.

Reboot and enjoy!

Howto add “Windows Entry” in GRUB2 ?

Edit the /boot/grub/grub.cfg file!

# nano /boot/grub/grub.cfg

Add this at the end of your /boot/grub/grub.cfg

# (2) Windows XP
menuentry "Windows XP" {
set root=(hd0,1)
chainloader +1
}

With Windows Vista, via EasyBCD and NeoGRUB

Since EasyBCD's NeoGRUB currently can't understand the GRUB v2 menu format, chain-load to it by replacing the contents of your "C:\NST\menu.lst" file with lines similar to the following:

default 0
timeout 1
title       Chainload into GRUB v2
root        (hd0,1)
kernel      /boot/grub/core.img

Grub2 has a new concept of root partition detection.

Unlike previous version of GRUB, if your XP is in hd1 or sda1

then put hda1 and sda1 and not hd0 /sd0