process for creating GRUB boot floppies as workaround for failure

grub_floppy_procedure (text/plain), 5.94 KB, created by arthur_torrey on 2006-09-23 18:50:49 UTC

GRUB Hard Disk Error

You set everything up the way you thought it should be, rebooted and got the above error.  This assumes that you can chroot into the hard drive installation, read and write to the drive, and otherwise are sure that the system is working properly, especially without hardware problems.

According to the GRUB manual, this means "The stage2 or stage1.5 is being read from a hard disk, and the attempt to determine the size and geometry of the hard disk failed."

In other words GRUB found a drive with GRUB in it's root (presumably your desired boot drive, and attempted to load.  It was not able to figure out the drive specs, and thus was not able to load finish loading.  Fortunately this error is apparently rare as it appears to be related to hardware interactions more than software configuration.  This is a very fundamental error, it is possible that you may have other things misconfigured, but that almost doesn't matter at this point because GRUB isn't getting far enough into the boot process to see them.  It says that GRUB has started to load but failed before it even got to look at your grub.conf or menu.lst file, let alone try to load anything.

It may be worth contacting the technical support departments of the system maker, or both the hard drive and motherboard manufacturers.

The first step will vary depending on your hardware.  Go into your BIOS, and look at the hard drive configuration, If it is set to any kind of automatic detection, attempt to change it to manual configuration, using LBA addressing, and the same drive parameter numbers that the autodetection routine supplied.  It has been reported that some BIOS's will report the drive parameters to GRUB in a way that confuses it, and manual configuration MAY give a better result.

If this does not work, create a minimal GRUB boot floppy to see if it is possible to boot the hard drive from the floppy. In order for this to work, your system must have a boot order that attempts to boot off the floppy before the hard drive, so ensure this is set up in the BIOS.  You will also need to know your boot partition (in GRUB notation) and kernel name.

Note 1: This procedure assumes that you have installed GRUB and set up a grub.conf file per the procedures described in the Gentoo Installation Manuals.  If you didn't do this, make appropriate changes.

Note 2: I presume that it would be possible to make similar types of GRUB boot CD's, but I have not attempted to do so.  This process deals with boot floppies only.  (IMHO, a floppy is better suited for this task if your machine has one)

Note 3: On a hard drive setup per the Gentoo Install Manual, the actual menu information is contained in the grub.conf file.  The official GRUB documentation calls for the menu information to be in a file called menu.lst.  For reasons I don't understand, the Gentoo dev's have made menu.lst a logical link to grub.conf, and put the menus in grub.conf.  To keep things simple, I am discarding this practice on the boot floppy and just keeping the menu information in menu.lst.

1. Reboot off the install CD, mount your partitions and chroot into the hard drive install.
2. Insert a dos formatted floppy into the floppy drive. (other formats may work as well)
2.[mymachine ~]# cd /boot/grub
3.[mymachine grub]# cat stage1 stage2 > /dev/fd0

Reboot the machine, you should see a message "GRUB Loading stage2" followed by a GRUB prompt screen. (I am assuming your boot partition is /dev/hda1, adjust as needed for your system configuration)

1. grub> root (hd0,0)
(you should get a message about your boot filesystem and partition type
2. grub> kernel /mykernelname <kernel parameters (if any)>
(another message describing your kernel)
3. grub>
(Note, most instructions on manually booting with GRUB call for you to specify the root partition on the command line (2 above) in Linux notation (i.e. root=/dev/hda5) as a kernel parameter.  I did not find this necessary, your mileage may vary)

It is also possible to boot other operating systems manually from the GRUB prompt by following the appropriate command sequences.  See the grub documentation <http://www.gnu.org/software/grub/manual/grub.html> for appropriate command sequence suggestions.

If this works, then your install on the hard drive is basically correct.  You can either continue to boot this way, or create a full GRUB boot floppy that will give you the splash screen and menu selection setup described in the Gentoo manual.  This is an ugly hack of a solution, but it does work.

To create a complete GRUB floppy:

1. Boot into Linux, if needed, mount all partitions, including /boot
2. Insert a floppy in the floppy drive.
3. [mymachine ~]# fdformat /dev/fd0
(see floppy formatting info on screen)
4. [mymachine ~]# mkfs.ext2 /dev/fd0
(see fs info on screen). ( Note, one could make other filesystem types (ext3, reiser, etc), but there is no advantage to doing so.  Ext2 is possibly faster on a floppy since it avoids journaling, and the extra time needed to occasionally fsck it is negligible - keep it simple!)
5. [mymachine ~]# mount /boot #(if it isn't already)
6. [mymachine ~]# mkdir /mount/floppy #(if needed)
7. [mymachine ~]# mount /dev/fd0 /mnt/floppy
8. [mymachine ~]# mkdir -p /mnt/floppy/boot/grub
9. [mymachine ~]# cp /boot/grub/stage* /mnt/floppy/boot/grub
10. [mymachine ~]# cp /boot/grub/menu.lst /mnt/floppy/boot/grub
11. [mymachine ~]# umount /dev/floppy

At this point we have a floppy with the files GRUB needs on it, but now we need to set it up.

1. [mymachine ~]# grub
(starts GRUB and brings you to a grub prompt)
2. grub> root (fd0)
3. grub> setup (fd0)
4. grub> quit

The machine can now be rebooted as needed.  The GRUB floppy must be in the drive anytime the machine is being booted, but it is not mounted and can be removed at any time when the machine is running. 

If you add additional kernels or make other changes that cause you to want a different boot menu, simply mount the GRUB floppy and edit menu.lst as needed.  There is no need to rerun the GRUB setup process a second time.