Creating Boot CDs

If problems occur while booting your system using a boot manager or if the boot manager cannot be installed on your hard disk disk, it is also possible to create a bootable CD with all the necessary start-up files for Linux. This requires a CD writer be installed in your system.

Creating a bootable CD-ROM with GRUB merely requires a special form of stage2 called stage2_eltorito and, optionally, a customized menu.lst. The classic files stage1 and stage2 are not required.

Procedure 17.7. Creating Boot CDs

Change into a directory in which to create the ISO image, for example: cd /tmp
Create a subdirectory for GRUB and change into the newly created iso directory:
```
mkdir -p iso/boot/grub && cd iso
```

Copy the kernel, the files stage2_eltorito, initrd, menu.lst and message to iso/boot/:

cp /boot/vmlinuz boot/
cp /boot/initrd boot/
cp /boot/message boot/
cp /usr/lib/grub/stage2_eltorito boot/grub
cp /boot/grub/menu.lst boot/grub

Adjust the path entries in boot/grub/menu.lst to make them point to a CD-ROM device. Do this by replacing the device name of the hard disks, listed in the format (hdx,y), in the pathnames with (cd), the device name of the CD-ROM drive. You may also need to adjust the paths to the message file, the kernel and the initrd—they need to point to /boot/message, /boot/vmlinuz and /boot/initrd, respectively. After having made the adjustments, menu.lst should look similar to the following example:
```
timeout 8
default 0
gfxmenu (cd)/boot/message

title Linux
   root (cd)
   kernel /boot/vmlinuz root=/dev/sda5 vga=794 resume=/dev/sda1 \
   splash=verbose showopts
   initrd /boot/initrd
```
Use splash=silent instead of splash=verbose to prevent the boot messages from appearing during the boot procedure.

Create the ISO image with the following command:

genisoimage -R -b boot/grub/stage2_eltorito -no-emul-boot \
-boot-load-size 4 -boot-info-table -iso-level 2 -input-charset utf-8 \
-o grub.iso /tmp/iso

Write the resulting file grub.iso to a CD using your preferred utility. Do not burn the ISO image as a data file, but use the option for burning a CD image in your burning utility.