Finally managed to fix grub, at least the rest of the natty upgrade seems to have succeeded.
I had to use a different distro (systemrescue cd) to do the chroot and the first 'dpkg-reconfigure grub-pc' didn't seem to work, possible because of an error (could not write to /livemnt/boot). But after a second attempt, mkdir -p /livemnt/boot; mount -o bind /boot /livemnt/boot and a finale grub-install /dev/sda to be sure I have a working system again.
Attaching the output of 'debconf-show grub-pc' before attempting the fix.
Finally managed to fix grub, at least the rest of the natty upgrade seems to have succeeded.
I had to use a different distro (systemrescue cd) to do the chroot and the first 'dpkg-reconfigure grub-pc' didn't seem to work, possible because of an error (could not write to /livemnt/boot). But after a second attempt, mkdir -p /livemnt/boot; mount -o bind /boot /livemnt/boot and a finale grub-install /dev/sda to be sure I have a working system again.
Attaching the output of 'debconf-show grub-pc' before attempting the fix.