(In reply to comment #21)
> Hi Seth,
> 
> the output is:
> bios vendor: Apple Inc.
> system product name: iMac12,1

Rats, it turns out there's more information required. If you can boot into OS X
and run the following command in a terminal, it's supposed to give all the
required information.

sudo ioreg -lw0 |grep manufacturer|cut -b25-80;sudo ioreg -lw0|grep
"product-name"|cut -b 25-80;sudo dtrace -qn 'BEGIN{boot_args=((struct
boot_args*)(`PE_state).bootArgs);printf("FrameBuff erBase:
0x%08x\nPixelsPerScanLine: %d\nHorizontalResolution: %d\nVerticalResolution:
%d", boot_args->Video.v_baseAddr, boot_args->Video.v_rowBytes/4,
boot_args->Video.v_width, boot_args->Video.v_height);exit(0)} '

> Could that also explain why X is not working?

I don't know much at all about X, but I suspect it might be at least
contributing. Maybe X is also trying to use the Intel graphics based on the
same information.