MacBook Pro EFI Firmware 1.8 boot fail
Apple released EFI Firmware update 1.8 on December 8 to eliminate the noise made by the optical disk drive during wake from sleep on MacBook Pro.
When rebooting for the firmware upgrade, one of our computers failed and did not boot. There was a long tone (expected for the upgrade), then three tones in a row. Three beeps means there is a RAM problem with the computer.
From Apple KB article HT2341:
Some RAM may appear to pass the Power-On-Self-Test (POST) but still cannot be used by the operating system. In this case, the computer will display a gray screen, sound three tones and blink the power LED on the front of the computer three times, pause, and repeat the blinking until the computer is turned off.
The memory in the laptop was not modified, and not third party (which may cause this boot problem).
To resolve the issue, we removed and reseated the memory.
I am not sure if this will work with all cases of Firmware 1.8 boot issues, but it fixed on of our systems.