Firmware updates can be found at http://www.apple.com/support/downloads/ or by choosing Software Update from the Apple menu.
To find out which version of firmware you have, see this article.
Make sure that your AC adapter is plugged in. The Firmware Updater application will not run unless the computer is connected to AC power.
- Locate the appropriate update for your computer. Download it to your computer by clicking the update's title, then click the file size indicator in download details or at the bottom of the page. The download will place the disk image with an installer in your downloads folder or the location specified in Safari General Preferences. If you downloaded the disk image via Safari, Safari will notify you that an application is in the image. Click OK to continue.
- If "Open safe files after downloading" is checked in Safari preferences, the disk image file will mount by itself. If that preference is not enabled in Safari, double-click the disk image to mount it.
- On the mounted disk image, you will see a file named MacBookFirmwareUpdate.pkg, MacBookProFirmwareUpdate.pkg or acBookAirFirmwareUpdate.pkg.
- Double-click the appropriate .pkg file to start the firmware update process. (The installer puts the Firmware Updater in the /Application/Utilities folder and opens it automatically.)
- Read the onscreen instructions and click Shut Down to proceed with the update. The firmware image will be loaded onto your computer. Your computer will shut down, but the update will not be installed until the next step.
- Turn on your computer but do NOT hold the power button down. The screen will turn black and remain in that state for up to 40 seconds. A gray screen will appear and a status bar indicates the progress of the update.
Important: Do not unplug, shutdown or restart your computer while the update is taking place.
Installation takes several minutes.
- After your firmware has been updated, your computer will restart.
- After you log in, a dialog box stating the firmware update has been successful will appear. Click OK to dismiss this dialog.
If there is an installation issue
If the update to your firmware was interrupted, your computer will beep 9 times when restarting (3 short, 3 long, 3 short) and the screen will be black. Your computer will attempt to recover by itself. It can take up to 30 seconds for your computer to restore the EFI Firmware to the previous version. Do not unplug your computer during this process. Your computer will restart by itself when the EFI Firmware is restored. After you computer restarts again, try installing again by opening the Firmware Updater application, which is located in the Utilities folder (/Application/Utilities). Then go to Step 4 above.
If you computer does not automatically recover, contact AppleCare for more information.
Important: An Intel-based Mac's hard disc must be formatted with the GUID partition scheme to apply a firmware update. Intel-based Macs are shipped this way from the factory. If you have reformatted your hard drive, you should check which scheme your hard disk is currently using before applying a firmware update. See this article for more information. If you try to apply the update to a hard drive that utilizes any formatting scheme other than the GUID partition scheme the update will be unsuccessful.
Some USB devices may prevent firmware updates from installing correctly. If you are having trouble installing an update, try disconnecting non-essential devices and use only an Apple keyboard, mouse, and display.