MacBook Pro EFI Firmware Update 1.9
This update is recommended for all 15-inch and 17-inch MacBook Pro mid 2010 models. The update resolves a rare issue that may cause the system to freeze during startup or intermittently stall during operation, and it improves compatibility with external displays.
The MacBook Pro EFI Update will update the EFI firmware on your MacBook Pro. Your computer's power cord must be connected and plugged into a working power source. When your MacBook Pro restarts a gray screen will appear with a status bar to indicate the progress of the update. It will take several minutes for the update to complete. Do not disturb or shut off the power on your MacBook Pro during this update.
See http://support.apple.com/kb/TS3423 for more information.