I had read all the comments thet said the HDD can be taken out at step 12, besides I'm in France, so I hadn't bought the special tool. when I realised I had to remove the logic board after all, I managed without the tool but I'm not doing it again. I inserted 2 screwdrivers in the holes and tried to move them both simultaneously. It worked but instead of sliding out slowly, the I/O board came out all the way with a noise! The clips from step 16 had unclipped by themselves, causing the noise. For a second I thought I had broken everything. I really don't recomment doing this without the tool.

Great guide, thanks!!

My experience when replacing the HDD:

- I didn't disconnect the fan, just moved it carefully around whenever it was in the way. However I had to unscrew the standoff screw - I just didn't understand how to move the fan without it

- Didn't disconnect the antenna plate either, just put it carefully aside

- I was really hoping to be able to skip steps 13 to 16 like many user comments suggest, but I couldn't. My 9.5mm HDD wouldn't get past the DIMM slots. I was trying to lift it up while sliding it out and there was 1mm or so of thickness that wouldn't pass, so I had to remove the logic board. However once I had inserted the new disc I realised I had forgotten to put back 2 screws from step 19. Without those the disk is loose, not really holding in place, so I didn't have to remove the logic board again. What is weird is I also managed to put it back with the screws, just by tilting the mac a little. So now I don't really know if I could have actually managed to pull it out at step 12..