Upgrading CentOS 4.0 to CentOS 4.1

CentOS 4 is basically Red Hat Enterprise Linux 4. I just upgraded it to CentOS 4.1 using the rpms using these steps:

• Download the rpms from CentOS/4.1/os on any mirror.
• Download the updates from CentOS/4.1/updates on any mirror.
• Download any extra modules that depend on the kernel version. In my case, I had to download linux-ntfs rpms for the 2.6.11ELhugemem kernel.
• Disable selinux using
  setenforce 0.
  (Failing to do this made the rpm postinstall fail for some rpm files. Off the cuff, I recall the rpms for bzip2-libs, and krb5-* failing.)
• From the directory containing the 4.1 rpms, run
  rpm -Fvh *.rpm
  You do need a lot of free disk space for this to work. Alternately, freshen a few rpms at a time :)
• Now enable selinux with setenforce 1.
  
• Reboot in run level 1 so that no services start up
• Run
  /sbin/fixfiles relabel
  Alternately, to speeden things up, you can also use
  /sbin/restorecon -R pathname
  to recursively restore security context on the specified path - in my case /lib and /usr/lib were definitely affected. I opted for the fixfiles approach rather than weed out directories individually.
• Change to the normal runlevel

That's all there is to it :-)