Updating Suse Linux 9.0 to 9.1

The .0 to .1 update suggests, that it's not a big deal. In fact, it is. Many things do brake and most people advise to do a clean install of 9.1. Because of extensive third party installations and customization I wanted to upgrade. In case the upgrade appeared unusable, I wanted to have the possibility to go back to 9.0. This appeared easily possible because we had a free 8.6 GB partition (hdb3) on the harddisk. Actually it was not free, but it was the root partition of our RedHat 9 installation. I did the following things:

1. I wanted to preserve all the user-specific configurations. Thus I backed up all the hidden files and directories from the main user's home directory: tar -cvf configuration_files.tar .[a-zA-Z0-9]*
2. Then I reformatted hdb3 (it was ext3) into reiserfs via Yast
3. Then went into runlevel 1 with sudo /sbin/telinit 1 and mounted the newly formatted partition mount /dev/hdb3 /redhat
4. Then I duplicated the current root partition (/dev/hdb2) cd redhat cp -ax / .
5. Then I edited /redhat/etc/fstab: I changed the entry for the root partition from /dev/hdb2 to /dev/hdb3. The current root partition (/dev/hdb2) uses already reiserfs, so no other changes are needed here. However, you have to uncomment all "special" file systems. Otherwise the Suse Installer will try to mount these and fail and then give you some bogus error messages. I had e.g. two entries for colinux (/dev/cob2 /) and got the following error message: " The root partition in /etc/fstab has a wrong root device. See http://portal.suse.com/sdb7en/2004/01/sata.html". Also special file systems create similar trouble. I first left the proc, usbfs, etc. entries and got again an error: "Partitions could not be mounted." Then I edited the fstab and left only /, /boot, swap, /home and then the Suse installer managed.
6. Then I edited /boot/grub/menu.lst and added an entry for the new system (I just duplicated the existing, renamed it and changed the root partition from to hda3; additionally I specified vmlinuz and initrd directly and not via symbolic links as the links will point to thefiles of the new kernel after the upgrade).
7. Before I started the actual installation I checked that I can select in grub both installations and successfully boot
8. During installation the installer complained about 1200 conflicts. Most of them I ignored as many packages of the old system had been manually added and were too new for the 9.1 installer CD. But since I was going to update online immediately after the install, this shouldn't be much of a problem. I also chose to keep installed packages that are not any longer maintained.