Apple has just released both EFI and SMC firmware fixes for the latest MacBook line (those released after January of this year). The updates are for the regular 13-inch MacBook, MacBook Air and 15-inch MacBook Pro.
The EFI updates issues with the stability of the systems, though there were no specific criteria. However, according to the Apple support boards, this may apply to systems that randomly freeze, especially those that are running more than the base amount of memory.
The SMS fixes improve the reliability of the MacSafe power connector’s indicator light, which lets users know when the battery is fully charged.
Each of the updates requires Max OS X 10.5.5 or later.
