This update is for iMac computers with Intel processors only.
Note: Print or write down these instructions before you begin the update.
To update the firmware on your Intel-based iMac:
1. Quit all other open applications.
2. Click Shut Down in the iMac EFI Firmware Update window and wait for your computer to shut down.
3. Press and hold the power button on your iMac until the power indicator light flashes repeatedly to begin the update.
A status bar indicates the progress of the update.
Important: Do not interrupt the update.
Your computer restarts automatically when the update is completed and opens the iMac EFI Firmware Update.
4. Click OK, if the firmware is now up-to-date.
If these instructions appear on your screen again, the firmware update was not successful. Repeat steps 2, 3 and 4.