Cannot finish installation on Asus P8Z68-V Pro & AMD Radeon 6950

[VelocityGirl]

Hi there. I'm having an issue; I can boot into my USB installation of Mountain Lion but after the installation is completed, I can't boot from the installed drive. The installation seemed to go smoothly - with all three monitors across two graphics cards working. Once I boot to the USB and then select the installed drive to boot from, even with -v it just gets to a white screen on one monitor, and the textured grey on the other. The mouse can move between screens but there are no menus or windows.

Here are my system specifications:

Asus P8Z68-V Pro (running latest BIOS, version 3402)
Intel Core i7 2600k
8 GB of RAM
AMD Radeon 6950 x2 in Crossfire
Plextor M3 Pro SSD

Any advice or suggestions on making this work or additional information I can provide?

Edit:

Boot flag results:

-v -x same
-v -x PCIRootUID=0 same
-v -x PCIRootUID=1 success! But keyboard doesn't work?!

Rebooted and used these flags again, and now back to grey screen and grey textured screen. Augh!

 

[VelocityGirl]

Okay, so I finished the installation and got into the OS. Not much was working - one monitor, no networking, no sound, no real graphics (although Radeon 6xxx detected in 'about this mac'). I used MultiBeast and the DSDT file on the site, but now when I reboot I just get NullCPUPowerManagement::start and then nothing. I'm going to reinstall again, and this time try MultiBeast's custom options. Any suggestions?

 

[beelzebozo]

You also need to install the NullCPUPowerManagement.kext located in MultiBeast.

 

[Te-Moz]

You will probably get no joy using the HD6950's.

You can read the full road of torture at netkas.org

In a nutshell HD6970/50's need a helper card or onboard GPU to get past the white screen bug in ML.
Even then some apps that use 3D either don't work well or have artifact problems.

netkas apparently made a an updated package from the MBP2012 update but I couldn't find it, so haven't been able to try that.
Even so a helper card is still needed to get past the white screen problem.

 

[VelocityGirl]

Is this correct then?

UserDSDT with DSDT from the database
NullCPUPowerManagement
OS X 10.7.4 Patched AppleIntelCPUPower...
hnak AppleIntelE1000e Ethernet

http://i.imgur.com/bSQGs.png

EDIT

This totally doesn't work... still just get to NullCPUPowerManagement::start. And that's if I boot from USB initially then boot from the driver; if I try to right to the drive I got a few lines of error and then nothing else; don't see Chameleon or anything else has been installed. Reinstalling once more <_<

regarding the 6950s - I don't mind too much if I don't get them fully working with 3D etc, as I just want to use the base OS for creative **** (writing, photoshoop, etc) and that seems to already be working right after installation, although only having one display fully working is a bit of a pain.

 

[samisnake]

the dsdt in the database does not match your bios, so itll cause the system to hang on boot.
boot in with -DSDT=null (type it in at the bootloader stage).

once you boot into osx, delete the dsdt from the extra folder.

you can either make your own dsdt, or run dsdt-less (this does not mean use easybeast- you dont need to use easybeast with your system). to make a dsdt, look at guide in my sig.

about nullcpu, patched appleintelcpu etc, read the thread in my sig entitled "asus bios repo". itll explain about power management on asus boards.

 

[Te-Moz]

If you want to get away from needing NullCPUmanagement all together you can flash your BIOS with one from samisnakes repository.

With a patched BIOS you don't need NullCPU kext or Patched Appleintelpowermanagement.kext
I have had mine patched for months and it works fine.

Edit: LOL there you go, help from allover

 

[VelocityGirl]

Thanks for the link to the patched BIOS - will have a look at that later.

At the moment, I'm having trouble even getting the install to work! It seems a bit random as to whether -x -v PCIRootUID=1 works; sometimes I get grey textured screen and sometimes I get the installer on top. I think the bare minimum I would want to get working is bootloader +sound + ethernet; could I do that just by installing a few options in Multibeast (e.g. not DSDT -or- EasyBeast?) If so, which options should I use?

 

[Te-Moz]

regarding the 6950s - I don't mind too much if I don't get them fully working with 3D etc, as I just want to use the base OS for creative **** (writing, photoshoop, etc) and that seems to already be working right after installation, although only having one display fully working is a bit of a pain.

I think you will find that Photoshop is one of the apps that has problems.

Having one display working would also fit with what others have found happens.

 

[Te-Moz]

At the moment, I'm having trouble even getting the install to work!

If you follow the directions in Colton328's thread, you will be able to get your install to work.
It is after the install that I ran into the white screen problem, and had to go researching and found out that HD69xx have a major flaw.

Best of luck, and let us know how you get on.