I have updated my MacBook Pro (Core i5, early 2010) with system update to new EFI version, and now after startup it just shows the gray screen and doesen't react on keyboard (just plays the boot sound).
I cannot open boot menu (Option key) and cannot boot from other device. Command+S does not help. Only thing that it reacts is Command-Option-P-R, but then it still won't boot.
Tech details: Installed 8 GB memory and 120 GB vertex2 SSD drive