Mountain Lion installation white screen grey square

[jam3l]

I am trying to install Mountain Lion on my Hackintosh that was previously running Lion. I could not reach the installer from my Unibeast flash drive, so i followed the advice of:
http://www.tonymacx86.com/mountain-...mountain-lion-6xxx-gpu-issues-fix-inside.html

and it worked, i was able to get to the Mountain Lion installer. I chose the SSD that i had had lion installed on and then the installation begun. Exactly 7 minutes before the estimated time of finish, the screen went white and a single grey square appeared on the screen (picture attached below) i have tried the installation twice and each time at the 7min point i get a white screen with a grey square. Please any help would be greatly appreciated.

My specs:
16GB Corsair Vengeance 1600Mhz Ram
AMD Radeon HD 6870 1GB DDR3
Gigabyte GA-Z68XP-UD3 rev 1.3 F8
intel core i7 2600k

 

[jam3l]

I tried: -v PCIRootID=1 GraphicsEnabler=Yes and it printed a lot of text on the screen and its been sitting idle for a few minutes.

 

[jam3l]

Still no luck. This time it was six minutes away from finishing the install.

 

[Gadogado]

I have exactly the same problem. Does anyone know how to get past the white screen with the little grey square?
My specs: Acer Aspire 7741G-454G, Core i5 450M, Radeon HD6550M

 

[Going Bald]

I chose the SSD that i had had lion installed on and then the installation begun. Exactly 7 minutes before the estimated time of finish, the screen went white and a single grey square appeared on the screen (picture attached below) i have tried the installation twice and each time at the 7min point i get a white screen with a grey square. Please any help would be greatly appreciated.

It is possible that the display is trying to go to sleep. I make it a habit to move the mouse roughly every 4-5 minutes during install to prevent this after several attempts to install resulted, I thought, in failure just before the install finished. Turned out it was the display turning itself off because of lack of action.