ACPI is for power management in boards that have that setting available... otherwise the x86PC boot flag disables this check.

You can write this to your com.apple.Boot.plist file by opening up Terminal and typing:
then simple use your keyboard arrows to get to the kernel flag section and modify it...
to save: [ctrl]+[o] then hit enter to save over the old one
to exit: [ctrl]+[x]

now reboot and you shouldn't need to do enter it in.

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