Resend as there has been no reply, with added info.
I finally said to hell with it and let F12 install itself on /dev/sdb
with all its defaults.
I was surprised on the reboot when my usual grub menu from
/dev/sda was all that showed up, no mention of an F12 install at all.
Added: I had it install everything in the options list, but gave it only
/dev/sdb to play with in the available disks menu's, & use the defaults on
/dev/sdb, so it made a 100 meg /boot, using ext4, and a logical volume out
of the rest of the drive. I have NDI how to query the filesystem used there,
other than trying to mount /dev/sdb1 as ext3 fails.
So, since I had blown away a centos install to put F12 on /dev/sdb, I
carved up a fresh grub stanza that reads like this and added it to
# grub.conf generated by anaconda
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You have a /boot partition. This means that
# all kernel and initrd paths are relative to /boot/, eg.
# root (hd0,0)
# kernel /vmlinuz-version ro root=/dev/sdb3
# initrd /initrd-version.img
#21 new stanza
title Fedora 12 (188.8.131.52-162.fc12.x86_64 from dev/sdb)
kernel /vmlinuz-184.108.40.206-162.fc12.x86_64 ro root=/dev/mapper/vg_coyote-
lv_root LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc
KEYTABLE=us rhgb quiet
which is in fact pasted from the /dev/sdb1/grub/grub.conf except for the
initial "root (hd1,0)" statement.
So it looks as if I might have to 'chainloader +1 ' it instead, so how
do I do that? I've never done that before.
Also, that /dev/sdb1 partition only mounts as ext4 if that is important.
Added: I experimentally added a 'chainloader+1' as the next line after the
root (hd1,0) in the /dev/sda1/grub/grub.conf, but all that seemed to do was
add another 10 second delay before I get the error 13 message. I would have
thought from what little I know about grub, that this should force a reload,
effectively a grub restart, from the mbr of /dev/sdb. Is there something I
need to change in the /dev/sdb1/grub/grub.conf also?