I've swapped the official 40GB disk for a shiny 160. 
But, it flops about in the PS2 when it's installed. Has anyone had any luck removing the rails from the official drive? The six bronze screws appear not to be Torx - tried with a small flat screwdriver but they don't budge.
Also, what is the lock / unlock thing about on the drive rails?

But, it flops about in the PS2 when it's installed. Has anyone had any luck removing the rails from the official drive? The six bronze screws appear not to be Torx - tried with a small flat screwdriver but they don't budge.
Also, what is the lock / unlock thing about on the drive rails?