seeing as you have a functioning osx install i would personally boot into safe mode -x and build a retail with just the chipset kext to see what is identifed with osx after updating to 10.5.5. This will eliminate any odd kexts that may have been used in the builds you are trying. Hers a brief guide.

http://www.infinitemac.com/f36/bare-...661/page5.html

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