I am trying to figure out why the savedefault cmd with the once option
is rendering my machine unbootable. Here is what I do first:
$GRUB_SHELL --batch --device-map=$GRUB_DIR/device.map <<EOF >> $GRUB_LOGF
root (hd0,2)
setup --stage2=$GRUB_DIR/stage2 --prefix=$GRUB_DIR (hd0)
quit
EOF
I omitted some steps (such as 'grub-install --just-copy') but basically
this successfully installs onto all 4 HDDs. (hd0,2) is the / partition
and is a RAID1. $GRUB_DIR is /boot/grub which is on the / partition
mentioned above. grub.conf is setup to boot entry 4 by default and
menu.lst is linked to grub.conf. I don't think the contents of these
files is bad because the system boots into the grub menu with entry 4
highlighted no problem and can boot into any image selected.
If, however, I issue the following command after the above install batch
command:
$GRUB_SHELL --batch --device-map=$GRUB_DIR/device.map <<EOF >> $GRUB_LOGF
root (hd0,2)
savedefault --stage2=$GRUB_DIR/stage2 --default=0 --once
quit
EOF
My machine hangs at the subsequent boot after the loading stage2 message.
device.map looks like this:
# leading comment
(hd0) /dev/hda
(hd1) /dev/hdb
(hd2) /dev/hdc
(hd3) /dev/hdd
In trying to figure out what happened by running the savedefault cmd I
looked at the stage1 sector and mapped it to the byte offsets in the
grub documentation. Viewed with 'hexdump -x', here is the boot sector:
offset value
------ ------
3e 0203
40 00
41 80
42 8000
44 4b4c 0003
48 eafa 7c50
1fe aa55
I tried to find stage2 using 'dd if=/dev/hda seek=<different variations
of the value (in decimal) found at offset 44>' and viewing it with
hexdump but I must be missing something because I wasn't seeing anything.
My questions:
-how to find stage2 on disk so I can verify that the saved entry byte is
the only thing that changes when I do the savedefault?
-what am I doing wrong with the savedefault command (with the --once
option) that is causing it to fail boot after running it?
I can supply more details if needed...
thanks!
Brett
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