Whenever I need to do a complete backup/copy of an installation, as you're doing here, I use a PartitionMagic floppy to copy the entire partition into a different hard drive. That way, if the upgrade fails, I can copy the partition back to restore the system exactly as it was just before the major upgrade.
Note that, because of the way that linux assigns partition numbers, the best way to restore a partition in this scenario is:
1. Delete the original, now messed up partition.
2. Copy the partition from the the secondary disk into the same location as the original partition on the primary disk.
This ensures that the restored partition has the same number and other attributes of the original partition. And your existing lilo config should work, with no changes.
As long as you followed the instructions in UPGRADE.TXT exactly, it should have worked fine.
1. Upgrade glibc libraries first.
2. Upgrade pkgtools second.
3. Upgrade/Install New sed-* packages
4. Upgrade everything else
You also might want to check within the /etc/ directory (and its subdirectories) for ".new" files, which are the new versions of config and startup files. You'll want to synch up each of your existing config and startup files with their ".new" counterparts. Basically, migrate your customizations and settings into the newer versions.
I usually use vimdiff to compare the two files and then manually change the appropriate settings in the new files.