Paul, What do you have for your /boot/grub/grub.conf and your /etc/sysconfig/grub. I have... default=0 timeout=10 splashimage=(hd0,0)/grub/splash.xpm.gz title Fedora Core (2.6.10-1.771_FC2smp) root (hd0,0) kernel /vmlinuz-2.6.10-1.771_FC2smp ro root=/dev/md1 rhgb quiet initrd /initrd-2.6.10-1.771_FC2smp.img ..etc for /boot/grub/grub.conf and... boot=/dev/sda forcelba=0 ...for /etc/sysconfig/grub. I am still a tad unclear on the upgrade the boot loader step. Does it effectively do an initial... grub Grub> device (hd0) /dev/sda Grub> root (hd0,0) Grub> setup (hd0) ...with essentially an empty grub.conf file? If so then I guess I should be okay since the installer must repeat those steps later when the kernel postinst script runs. Jack ps I have filed this problem under bugzilla... https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=163314 ...in case anyone else has any feedback to add. Oh, I looked in the postinst script for the FC4 kernels. They call /sbin/new-kernel-pkg which in turn calls grubby. Since the only time they use the --bootloader-probe option in /sbin/new-kernel-pkg is to look for lilo, I guess it should be okay. I do have backups by am trying not to need to use them.