Why You Might Need to Restore the Firmware
Apple supplies occasional updates, and although they’re not usually hard to install, problems sometimes occur. The most common problems are encountering a power failure during the installation process or turning off your Mac during the installation. Many Intel Macs that include a built-in CD/DVD drive can restore corrupt firmware to a known good state by using a Firmware Restoration CD available from Apple. Apple supplies the firmware as a download. You supply the CD.
Get Your Mac’s Model Identifier
There are six Firmware Restoration files that cover various Mac models. Before you can use the downloadable file, copy it to a CD or DVD. Then, if something goes wrong during an update, restart your Mac from the Firmware Restoration CD, and your Mac replaces the corrupt firmware with the known good version. To match your Mac with the correct file, you need to know your Mac’s Model Identifier, which you can find by performing the following steps:
Which Mac Firmware Restoration File to Download?
Depending on the Model Identifier you recorded, select the correct firmware download:
Firmware Restoration 1.9: Use with Model Identifier MacPro5,1 Firmware Restoration 1.8: Use with Model Identifier MacPro4,1, Xserve3,1 Firmware Restoration 1.7: Use with Model Identifiers iMac4,1, iMac4,2, MacMini1,1, MacBook1,1: MacBookPro1,1, MacBookPro1,2, MacBookPro3,1 Firmware Restoration 1.6: Use with Model Identifiers Xserve2,1, MacBook3,1, iMac7,1 Firmware Restoration 1.5: Use with Model Identifier MacPro3,1 Firmware Restoration 1.4: Use with Model Identifiers iMac5,1, iMac5,2, iMac6,1, MacBook2,1, MacBookPro2,1, MacBookPro2,2, MacPro1,1, MacPro2,1, Xserve1,1
If you don’t see your Mac model number in this list, you may have an Intel Mac that doesn’t allow firmware restoration by CD. Newer Intel Macs don’t use a restoration CD.
Creating the Firmware Restoration CD
Before you can restore your Mac’s firmware to its original state, you must first create a Firmware Restoration CD. The following steps take you through the process.
Using the Firmware Restoration CD
Before you begin the restoration, ensure that your Mac is powered from an AC outlet. Do not attempt to restore the firmware on a laptop while it’s running under battery power. Do not interrupt the process, disconnect power, use the mouse or keyboard, or shut down or restart your Mac during the restoration process. When the update is complete, your Mac automatically restarts.
Firmware Restoration on Newer Macs
When Apple removed the CD/DVD drive from Mac models, the company needed an alternate method of recovering from a corrupt firmware installation. Apple could have provided the firmware restore system on a bootable USB flash drive, but instead, it rolled the firmware recovery process into the Recovery HD hidden partition that is included with all newer Macs.
