原帖由： amatsuda ,
9 beeps in an SOS pattern (. . . _ _ _ . . .), a pause, then it repeating again usually means the EFI ROM is corrupted and the computer is in EFI ROM recovery mode. Give it a good hour to try and let the computer save itself. If you think you’ve waited long enough and it still hasn’t done anything, since you have a pre-2011 Mac, you should be able to replace the chip containing the EFI and the EFI ROM. I have no idea where to get one, unfortunately.