Yes,  I know it’s not supported, but neither is anything else. I took the time on friday to try out the yum update and it worked swimmingly. Here are the steps I took:

0. I ran pybackpack and duplicity and backed up all my stuff to remote

1. download fedora-release and fedora-release notes from the f12 mirrors

2. yum localinstall them

3. yum clean all

4. screen

5. yum update yum\* rpm\*

6. yum update python\*

7. yum update glibc\*

8. yum update kernel

9. yum update

10. yum groupinstall “GNOME Desktop Environment” base core

11. yum remove specspo mlocate sendmail

12. logout and reboot

It took a while to get everything and I had to break a few pieces up in order to make all the pkgs fit when I downloaded them but everything else just worked.

Proceed at your own risk.