agp0 hang in 5.2.1-RELEASE

Hi,

I am attempting to install FreeBSD 5.2.1 on a Gateway 7200 Server with
Dual P3 500 MHz.  It has onboard agp graphics by Cirrus Logic, the bios
has the onboard video disabled and has a pci ATI Xpert98 running
instead.  The server install correctly using the floppy disks, but once
it was rebooted the system hangs on agp0.  Is there any way to disable
agp at boot time, because I can not get to the src directory to
recompile the kernel without this option, I checked the documentation
and could not find any help there.  Any suggestions for a work around?

Thanks,

David