grub can't access system

[Jim Cornette]

korgull wrote:
> Hi,
> 
> I'm having one hell of a problem with my system after I tired to upgrade.
> Finally I reinstalled the system and moved my root partition to another 
> partition in order to save the data on the old partition (I didn't reformat 
> this partition during the reinstall, all other partions I reformated).

Did you give the old root partition a mountpoint? Or did you not assign 
your old / partition to anything? The third choice as to mount your old 
root as / without a reformatting of the partition would leave / as a mess.

> 
> Now grub boots with only a lot of "GRUB" on my screen and I can't access the 
> installed FC4 system.
> 
> My main harddisk is at /dev/sda and the current boot partition is /dev/sda5 
> (which is in an extended partition).

It is my understanding that the /boot partition has to be on a primary 
partition. When you go into rescue mode, does the system find both 
/mnt/sysimage and /mnt/sysimage/boot? When you chroot /mnt/sysimage is 
/boot loaded with the kernel and the grub subdrectory.
I'm not sure if this is the case since I have one installation that I 
believe is entirely within an extended partition. I use this partition 
as the main grub loader, which is installed in the master boot record.

  My old boot partition was /dev/sda2
> which for some reason is still found by the rescue disk as a valid boot 
> partition, although I have cleared all directories except my data from it 
> (how can I clear this ?)

Reformatting the drive will erase the old data. The volume will still 
probably have the /boot label assigned to it. Why not use this partition 
as your /boot partition for a new installation

> I also have an IDE drive installed as /dev/hda. I use this only for data and 
> don't want to boot from it. I hope that's fine with grub.....

This is kind of a situation with grub, computer BIOS and Linux. Some 
with both SATA (recognized as sda) and PATA (recognized as hda) can 
confuse grub with booting priority.  If reading other postings and 
understading the situation, grub is installed in /dev/hda with anaconda 
by default. Unless you use the advanced boot options to direct grub to 
be installed elsewhere.

> 
> I tried to reinstall grub by using grub-install, but it won't work.
> 
> Is there any way to fix this issue ?

BIOS boot device priorities must be set up correctly with both types of 
hard drives on your system. I believe your BIOS should have some feature 
to pick SATA over IDE as boot priority.
  When you boot from recue mode, you have to change to the directory 
which will be your new / (root) partition using chroot /mnt/sysimage 
before running grub-install. For your situation where /boot is installed 
within an extended partition, I would attempt to install grub to the MBR 
or the IDE drive (grub-install /dev/hda) after accessing the new 
installation with the rescue disk or (grub-install /dev/sda) to install 
it in the master boot record of the SATA drive.

Installing grub in the MBR only puts early stages of grub in it. The 
main work is performed from data within the /boot/grub directory of your 
installation. That is to say, it will hand off control to items within 
the /boot/grub directory.
Installing grub in an extended partition directly is beyond me. I think 
it is BIOS related rather than operating system limitations. Using the 
MBR instead leaves the OS more in control.

Hopefully I am not relaying any wrong information.

Jim

> 
> Regards,
> Marcel
> 


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