Step 6 is not working for me. The plastic port cover assembly is stuck in place, even when all 3 screws are removed. I have tried wedging plastic shims under the sides of the plastic assembly and it still will not budge. It is stuck in the middle somehow. Is there some mechanism holding it in, in the middle? Is there a mating plastic clip on the opposite side of the plastic port cover? How did you remove it?

Thanks.