Mid 2010 Mac Pro video boot issues...

iMav

macrumors 6502
Original poster
Jun 20, 2008
340
5
Columbus, WI


I have an issue with booting this system while monitor(s) (one or two) and plugged into the mini-Display ports. It will never boot. If I unplug them and plug in a monitor connected via DVI, it boots fine.

So, I have been keeping a spare monitor around for when I need to reboot. Unplug the two monitors, plug in the DVI-connected monitor, let it fully boot up, and then unplug that monitor and plug in the two monitors I actually use (which, then, work fine).

What is the deal???
 

h9826790

macrumors G5
Apr 3, 2014
12,787
5,600
Hong Kong
That's the problem, a flashed 7970 cannot boot with Mac EFI ROM if the 4K display connected and work at dp1.2 (4k 60Hz).

You can either disconnect the display. Set it to dp1.1 (30Hz only), and reset it to dp1.2 after boot. Or boot from the non Mac EFI room (no boot screen).
 

iMav

macrumors 6502
Original poster
Jun 20, 2008
340
5
Columbus, WI
I don't care if I see the boot screen or not. How do I set things up so that it boots from the non-Mac EFI rom??
 

h9826790

macrumors G5
Apr 3, 2014
12,787
5,600
Hong Kong
There should be a switch on your 7970, just next to the crossfire port.

If you buy the card with flashed ROM. Try to flip it to another position.

If you flash it by yourself. Then you should know if the other ROM has Mac EFI.

If no switch, or both are Mac EFI ROM. Then you have to dump the ROM, remove the EFI (or disable it), and flash the ROM back to the card.