[CentOS] A last, desperate hope - video modes

Hi, folks. This is, in fact, off-topic: I'm fighting a user's FC19 box. I
updated him, rebooted... and his ATI video card seems to not be supported
any more (and it's *not* that old - an RV620).

The thing that drives me crazy is, when I reinstalled the whole system,
whatever video driver the installer used for graphical install *worked*.
So: does anyone have any idea a) what driver that uses, and b) how to
force grub2 to use it (or do I also need to do this to the initrd)?

        mark

--
grub2 must DIE!