I am sad to say that I cannot get it to work.
Hooked everything up installing the Apple OEM 5770 card. Connected Apple Cinema Screen. Installed OSX. So far so good. Resolution only 1024 x 768 as expected.
Next step - I read this thread from start to finish:
viewtopic.php?f=15&t=5884
Installed 10.6.6 did not reboot - ran Multibeast 3.2.0. First problem ATY_Init.kext option is gone as well as others which were available when the other nice members were able to get their ACS to work in the above thread.
So ticked graphics enable = no, modified the ATY_Init kext to replace Vervet wit Hoolock. Modified the apple.boot .plist as follows:
<key>GraphicsEnabler</key>
<string>Yes</string>
<key>AtiFb</key>
<string>Hoolock</string>
<key>Graphics Mode</key>
<string>2560x1440x32</string>
Rebooted. Hangs on the grey screen apple logo every time. No spinning wheel. No means of safe booting with -x -v -f or any others for that matter.
Next approach fresh install after replacing the oem Apple 5770 with the original Radeon 5770 card hooked up to a standard monitor - get everything working and then drop in the modified ATY_Init.kext in through Kext installer and modify graphics = no using Multieast (repair caches etc) and add the above code. That was my cunning plan but..........
Shut down, replaced original Radeon with OEM Apple 5770 - connect all up and reboot . Hangs on the grey screen with Apple logo. Grrrrr
Variations on the above theme - with a boot file from Kabyl which took me ages to install to the root drive because there was an invisible boot file there already.
Not often I fail but cannot think of anything else to do. There boards are filled with tons of good advice but it is so jumbled and contradictory it is difficult to sort the wheat from the chaff.
So tomorrow the card goes back to Apple - and I'm going to order an Atlona AT-DP400 which is about the same price but is proven to work out of the box. Not the solution I wanted but what can one do when I've splashed out on a fabulous Apple monitor.