The osx update guide for Core2Dual system with EFI

Backup your drivers
Open Terminal
sudo -s
*type password*
In terminal, type:
while sleep 1; do rm -rf /System/Library/Extensions/AppleIntelCPUPowerManagement.kext; done

Open Update Installer
Run update BUT DO NOT RESTART
Go back to your terminal and press Control C to end the script
In terminal type:
nano /System/InstallAtStartup/scripts/1
Replace the line Dont Steal Mac OS X.kext with dsmos.kext
Restore your drivers
Restart and boot with -v
It will start loading and then you will get the message MACH_REBOOT, there you can hard reboot your computer. When you reach the darwin boot screen again, boot with -v again just for safe measure and it will boot fine.