I did exactly that with both HDD took them out and gave them a full format with my PC fat32 of course. When people are saying a bluray problem the discs do load fine. But there is a indentation on the main ribbon that go's from the logic board to the drive.
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I don't know if this can cause a problem at all. It was caught in between the drive and the black plastic screw mount that can bee seen in the back of the photo. Any thoughts on this?