I am the proud owner of an mid 2009 15” Unibody MacbookPro. If you do have one of these machines, DON’T take up the option of the 1.7 EFI firmware upgrade. If you do, your machine will spend a good amount of it’s time beach-balling intermittently while doing just about anything.

I made this mistake, and after some research, found a large group of disgruntled people with this problem too. Found a great fix though. There is an image that you can boot off (after restoring it to a small 1GB flash drive through disk utility) that will allow you to RETROGRADE the firmware. To 1.6 (the default FW that my machine shipped with , under Leopard 10.5.8 )

If you want to download the firmware boot image, you can grab it off my drop here:

http://drop.io/podrush/asset/aluminum-macbook-pro-recovery-dmg

I am now running SL and the beachballing stopped the moment I did this…