OK, I managed to modify my kernel configuration without updating LILO [by forgetting to do a simple 'lilo' at the root prompt]. Result? An unbootable GNU/Linux installation. Go me. Thank Light I have always a copy of the aquamorph livecd laying around, so I went trying to update the bootrecord from that booted cd.
At first it wouldn't work, but then I remembered some things about an earlier rescue operation. Here's what you need to do:
Boot your aquamorph, Morphix or whatever livecd, do a 'sudo bash' in a terminal [or at least get yourself a root terminal] and then mount the partition of your linux install [in my case /mnt/hda5]. Edit the /etc/lilo.conf file to represent this modified path to the kernel image [use nano instead of vim if you want ;)]
mount /mnt/hda5 vim /mnt/hda5/etc/lilo.conf [change image=/boot/vmlinuz-2.6.10-kanotix-4 to image=/mnt/hda5/boot/vmlinuz-2.6.10-kanotix-4 or whatever kernel you are using] lilo -C /mnt/hda5/etc/lilo.conf -i /mnt/hda5/boot/boot.b -m /mnt/hda5/boot/map -b /dev/hda
Reboot and boot your fixed installation. Don't forget to remove the "/mnt/hda5" again from the path to the kernel image in /etc/lilo.conf, otherwise you'll end up with a nonfunctional config file. Fetch yourself a beer.