Hello: I have an Mid 2009 Macbook Pro 15, which I cannot get updated to Mavericks..... Here are the details: - this computer had issues in the past with replacement HDs ( various WD Blue and Black models ). I had to downgrade EFI to 1.6 to make it work with WD 750GB Black. - I have tried in the past OS X 10.8, it failed ( many beachballs afer installation ), so I went back to 10.7 - now I would like to sell the computer, with a clean Mavericks installation - Mavericks install fails, the difference from the 10.8 installation is that the installation itself fails - I have even tried an Toshiba 500GB HD from my 2011 Macbook, same failure My guess is 10.8 and 10.9 do not play well with EFI 1.6. And I cannot go to EFI 1.7, unless I limit the SATA speed to 1.5 GBPS. I am wondering: - is there an HD or SSD, where the SATA negotiation can be forced to 1.5 GBPS ? Via jumper settings, or some engineering utility ? - any other advise ? Thanks, Paul.