I installed the ELSDR kernel from contrib.
It updates /etc/grub.conf fine, but makes
the default 1 (the old kernel).  So I change
the default to 0 and reboot, and get... the
old kernel.

There are only two kernels listed.  Both
were installed by rpm (one at kickstart
time).  Regardless of whether I set default
to 0 or 1, grub defaults to the second
(original, non-SDR) kernel.

I can manually select the SDR kernel when
the grub screen appears, but that's not really
a good option.

Here's an /etc/grub.conf from one of the
boxes:
----------------------------------------------------------------
# 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/hda2
#          initrd /initrd-version.img
#boot=/dev/hda
default=0
timeout=10
splashimage=(hd0,0)/grub/splash.xpm.gz
title Scientific Linux SL Release 3.0.4 (SL) (2.4.21-27.0.2.ELSDR)
        root (hd0,0)
        kernel /vmlinuz-2.4.21-27.0.2.ELSDR ro root=LABEL=/
        initrd /initrd-2.4.21-27.0.2.ELSDR.img
title Scientific Linux (2.4.21-27.0.2.EL)
        root (hd0,0)
        kernel /vmlinuz-2.4.21-27.0.2.EL ro root=LABEL=/
        initrd /initrd-2.4.21-27.0.2.EL.img
----------------------------------------------------------------

Any ideas?

Thanks,
Miles