Apple Computer on Monday posted firmware updates for all Intel-based Mac computers, but as usual was mum about exactly what the patches fixed.

The updates for the Mac mini, iMac, MacBook, and MacBook Pro lines of desktop and notebook systems can be downloaded directly from the Apple support site, or users can launch the update process from their machine's desktop.

Firmware is the collective term for the code on chips that retain their content without electrical power; that code is primarily used to boot the computer after it's switched on. Apple's Macs use the Extensible Firmware Interface, an Intel-designed firmware system intended as a replacement for the venerable BIOS long used by PCs. According to Apple, the firmware upgrades fix several issues in Boot Camp -- Apple's dual-boot application that lets users run Windows XP and Vista on an Intel Mac -- and in the start-up and wake-from-sleep processes. No other details were forthcoming.

The Cupertino, Calif. computer maker also updated its Firmware Restoration CD, a recovery disc only necessary if a firmware update was interrupted or failed.