Grub and Chainloaders

[Dan Thurman]

I have successfully arranged Grubs in the following way:

-Primary--Primary--Primary--Extended---------------------------------->
[boot-sys] [boot-f8] [boot-f9] [ [root-f8] [root-f9] [f-App1] [swap] ]

boot-sys:
================================================
[...]
#boot=/dev/sda
timeout=10
default=saved
splashimage=(hd0,0)/grub/splash.xpm.gz
#hiddenmenu
title Fedora 8
    norootverify (hd0,1)
    chainloader +1
title Fedora 9
    norootverify (hd0,2)
    chainloader +1
================================================

boot-sys has grub/grub.conf but no initrd/kernels installed
and boot-f8/9 partitions has the normal initrd/kernel/grub.conf
installed.  It all works great.

But on a different system, I tried a different setup:

-Primary--Primary--Primary--Extended---------------------------------->
[    XP   ] [ Vista ] [boot-sys] [ [w-app1] [boot-f9] [boot-f10] 
[root-f9] [root-f10] [f-App1] [swap] ]

boot-sys:
 - I left the original f9 xinitrd/kermel/grub.conf in boot-sys and
   modified boot-sys's grub.conf as follows:

boot-sys:
================================================
[...]
#boot=/dev/sda
timeout=10
default=saved
splashimage=(hd0,2)/grub/splash.xpm.gz
#hiddenmenu
title Fedora 9
        norootverify (hd0,4)
        chainloader +1
        savedefault
title Fedora (2.6.26.5-45.fc9.i686)
        root (hd0,4)
        kernel /vmlinuz-2.6.26.5-45.fc9.i686 ro root=LABEL=root-f9 rhgb 
quiet
        initrd /initrd-2.6.26.5-45.fc9.i686.img
        savedefault
================================================

I can boot F9 via the second title definition, but when I attempt
to boot using the first title definition (using chainloader +1),
grub complains:

Error 13: Invalid or unsupported  executable format

Thinking that the chainloader +1 was not finding the right
partition, I assumed that +1 means to locate the next partition,
so I tried values of 2,3,4, and 5 and they all reported the same
error.

I wonder if perhaps grub is unable to reach the partition beyond
a fixed size (my MB+BIOs is as new as 2 months ago, so I surmise
it isn't a BIOS limitation), or grub cannot reach into extended
partitions, or if it can, maybe I will need to move the boot-fX
to the beginning of the extended partitions.  In any case, I know
that moving boot-fX into it's own primary partitions works but
then I won't be able to add XP or Vista into its own primary
partitions and would have to get a second drive separating
windows from Fedora which I know will work.

But I'd prefer to not to buy a second drive at this time, so the
question is, does anyone have any idea what is going on or
have any suggestions how to get this to work?

Thanks!
Dan