Graphics mayhem on ML boot

[Hackakiri]

Hi!
I succeeded in installing 10.6.8 without any big troubles, my only concern is about my graphics issue on ML boot.
When i see my login screen the screen seems to be only 25% of the total screen: i only see the upper left!
Once i log in, i have to make a cmd+space to launch spotlight and blindly write (because spotlight appears on the upper right that i can't see) preferences.
Then i manage to go in displays and scale to 1600 resolution then i go back to 1900 resolution and the screen sets up correctly.
How can i fix that without risking any loss in an otherwise 100% working Hackintosh?
Thanks for your help.

 

[Hackakiri]

Still testing:
with <key>Graphics Mode</key>
<string>1920x1080x32</string>

in org.chameleon.Boot i boot with a silver Apple logo i never saw before and resolution isn't weird, it's just in 1024x768.

When i boot with GraphicsEnabler=No it gives the same poor resolution 1024x768.

I really don't understand why i must choose between what seems a 4096x3072 (i only see a quarter of my screen at full resolution) and a lousy 1024x768 resolution
Curious to see the org.chameleon.Boot of a 100% working Z68X-UD3H-B3 running ML...
Mine is:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>EthernetBuiltIn</key>
<string>Yes</string>
<key>GenerateCStates</key>
<string>Yes</string>
<key>GeneratePStates</key>
<string>Yes</string>
<key>GraphicsEnabler</key>
<string>Yes</string>
<key>Kernel</key>
<string>mach_kernel</string>
<key>Kernel Flags</key>
<string>darkwake=0</string>
<key>Legacy Logo</key>
<string>Yes</string>
<key>Timeout</key>
<string>2</string>
<key>UseKernelCache</key>
<string>Yes</string>
</dict>
</plist>

Anyone knows what i should change to have a normal boot?