Phillips #00 is the right tool for all the steps (Except the 4 HD T6 screws). Maybe there is dirt in the notch.
I just used this guide to replace my HD with a 1TB SSDH. Smooth process since I had already upgraded RAM (16GB) and changed the battery. I got an USB Universal Drive Adapter, cloned my old disk, swapped drives, and ready to go.
Thanks iFixIt, my MBP Mid 2010 has a new life for under $250.
Had no problem disconnecting the cable, I used a nylon spudger to press the connector down while using a plastic pry tool to pull the cable up, be patient, it might take time.
Tip for reassemble: Use a tweezer to reinsert the cable, again, it might take time.
One tip when reassembling. These screws are very tiny and difficult to handle even with magnetized drivers, so I used the PH000 tip of the iFixIt kit to pick the screws and screw the first turns. Then switch to a PH00 to tighten them. Actually, using a PH00 of a cheaper set I bought to open the iPod, worked better since the length of the screwdriver was shorter than the case.
I saw some YouTube videos where they were able to reuse the black tape on the new backplate, so I took some time to carefully remove it, without success. However, since I was replacing my iPod 7th Gen with a 240GB disk (thicker than the original), the new thicker back plate did not need the tape since the cables are separated form the case.
There are several hard tasks in this process and this step was hard for me. Took me a while to detach the battery without damaging the cables. But with some patience I succeeded.
Great guide, by the way.
A very easy and fast update indeed! Using this guide and the tools indicated on top I replaced the two RAM cards (2GB each) with two 8GB RAM cards from OWC for a total of 16GB RAM in my MBP Middle 2010 Core 2 Duo (Officially not supported according to Apple).
Make sure you select RAM with these specs: 16GB DDR3 PC8500 1066MHz Kit (8GBx2)
Apps open much faster and I can run a virtual machine at a decent speed.