How to create a GRUB bootable CD?

**RMG** · 21-01-2009

I had installed linux OS which had grub as a bootloader. i messed with some configuration and now i'm stuck. my computer won't load. i know the changes which i made and i can fix it through grub bootable [did that several time before]. but i've misplaced my grub bootable cd. can anybody help me with this??

**SalVatore** · 21-01-2009

GRUB supports the no emulation mode.This means that you can use the whole CD-ROM from GRUB and you don't have to make a floppy or hard disk image file, which can cause compatibility problems.For booting from a CD-ROM, GRUB need to have stage2_eltorito and optionally a config file.

Here is an example of procedures to make a bootable CD-ROM image. First, make a top directory for the bootable image.

Code:

$ mkdir iso

Make a directory for GRUB:

Code:

$ mkdir -p iso/boot/grub

Now copy the file stage2_eltorito:

Code:

$ cp /usr/lib/grub/i386-pc/stage2_eltorito iso/boot/grub

If desired, make the config file menu.lst under iso/boot/grub.

Code:

# Sample boot menu configuration file

# By default, boot the first entry.

default 0

# The first entry as counting starts with number zero, not one.

# Boot automatically after 30 secs.
timeout 30

# GRUB will boot automatically in 30 seconds, unless interrupted with a keypress.

Finally, make a ISO9660 image file like this:

Code:

$ mkisofs -R -b boot/grub/stage2_eltorito -no-emul-boot \ -boot-load-size 4 -boot-info-table -o grub.iso

**RMG** · 21-01-2009

Hey thanks man! i'll try it out as soon as i get on my PC. Actually i'm not very familiar with linux OS, wanna know why "load size 4" option is used to make bootable image? is it necessary?