Does the parts kit work for upper and lower drive bays?

You are correct! There are two different SATA ribbon cables (one for each bay).

Please take both out (keeping clear which came from which system). Carefully flatten them out so you can take a good clear photo of each. I would hold a ruler against each of them for size reference. Please supply the last four digits of each systems serial number (on the pics) and post them here.

Then post a message to the Store Click Here put a link to this posting in the message.

With your help we can address the confusion others have faced and also get each cable available from the IFIXIT store.