I recently installed a Seagate 500GB 7200.4 hard drive without the g-sensor. I've noticed however that I could not purposely nor accidentally "trip" the SMS that is built into the aluminum unibody macbook; I do remember being able to rip the original one that came with the purchase. I checked the SMS in the terminal and it is activated. Could anyone please help me understand? Also, is there anyway to install the Macbook Pro Hard drive Update onto a unibody macbook? Thank you so much in advance!!!