I've just made the download and installation of this firmware from Apple. It asked me to restart the computer then appeared another installation process with a warning for me don't boot the system till the process is done. One more boot and I got a message like "You installed a software for a hardware that doesn't exist" or something like that. I booted again and the same message appeared. And I got a system crash, not during the installation process, but I think the system turned uninstable after the update. Anyone with the same problem ?