Bypassing a cranky BIOS: boot from CDROM

After a major crash of our Acer Aspire 1642 the hard disk needed to be replaced. After booting from a life CD we successfully installed Ubuntu Gutsy on the new drive. Unfortunately, after reboot the BIOS appeared to be completely blind to it. A BIOS upgrade would not fix the problem.

We worked around the problem by creating a boot CD that would load a kernel, recognize the drive and continue booting the root partion on it.

First install the package syslinux.

Create a working directory:

mkdir bootcd

Add isolinux.bin:

cp /usr/lib/syslinux/isolinux.bin bootcd

Copy the appropriate kernel and ramdisk images to bootcd/linux and bootcd/initrd.img respectively, e.g:

cp /boot/vmlinuz-2.6.22-14-generic bootcd/linux

cp /boot/initrd.img-2.6.22-14-generic bootcd/initrd.img

Create a file bootcd/isolinux.cfg containg a line that will point to your root partition, e.g. /dev/sda1:

DEFAULT linux initrd=initrd.img ro root=/dev/sda1

Create an iso image of the working directory:

mkisofs -o bootcd.iso -b isolinux.bin -c -no-emul-boot -boot-load-size 4 -boot-info-table -J -hide-rr-moved -R bootcd/

Burn the image to CD.

Boot your system.

2 thoughts on “Bypassing a cranky BIOS: boot from CDROM”

  1. Of course this CD needs to be updated after kernel upgrade or reconfiguration…

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