Mac firmware revive and restore
Overview
Mac computers with Apple silicon or the Apple T2 Security Chip include firmware that controls low-level hardware functions. If this firmware becomes corrupted, the Mac may fail to start up. You can revive or restore it using a second Mac.
A revive updates the firmware and retains user data, if recoverable. Use revive before restore.
A restore erases the Mac before reinstalling firmware, leaving all data unrecoverable.
Important: Only attempt a restore if a revive doesn’t resolve the issue.
What a restore reinstalls depends on the chip. On a Mac with Apple silicon, a restore reinstalls firmware and macOS. On a Mac with the T2 chip, a restore reinstalls only the T2 firmware. macOS can be reinstalled afterward using macOS Recovery.
Requirements and expected behavior
You can revive or restore an affected Mac from a host Mac using either the Finder or Apple Configurator. Both methods support a Mac with Apple silicon or a Mac with the T2 chip. Whether you use the Finder or Apple Configurator, unless you have already downloaded it, the host Mac downloads the firmware from Apple and saves it on the host Mac before the revive or restore begins.
The path to firmware downloaded using the Finder is:
~/Library/iTunes/The path to firmware downloaded using Apple Configurator is:
~/Library/Group Containers/K36BKF7T3D.group.com.apple.configurator/Library/Caches/Firmware/
Firmware revive and restore requires the following:
Affected Mac: A Mac with Apple silicon or the T2 chip.
Host Mac: Any Mac with macOS Sonoma 14 or later and a reliable internet connection.
Cable: A USB-C cable that supports both data and charging, such as the Apple USB-C Charge Cable. Don’t use a Thunderbolt 3 cable.
Power: Connect both Mac computers to a power source during the process.
Note: The DFU port location varies by Mac model. To identify the correct port on the affected Mac, see the Apple Support article How to identify the DFU port on Mac.
Users may report
Several symptoms may indicate a firmware issue. Users may report a Mac that starts up to an exclamation point in a circle, or one that turns on but starts up to a blank screen. A macOS installation may stop before completing.
Users may also note the status indicator light rapidly flashes amber or is solid amber and the display may show a blank screen. For more information, see the Apple Support article Mac computer status indicator light behavior.
Note: A blank screen at startup has other causes. See Diagnose Mac startup issues before proceeding.
Isolating the issue
Before beginning firmware revive or restore, confirm the following:
Confirm the Mac model: Firmware revive and restore is only available on Mac computers with Apple silicon or the T2 chip. Check the Mac model in How to identify the DFU port on Mac to confirm compatibility.
Rule out other causes: A blank screen or startup failure may have causes unrelated to firmware. Review Diagnose Mac startup issues before attempting firmware revive or restore.
Confirm a host Mac is available: You need a second Mac with macOS Sonoma 14 or later and a reliable internet connection.
Troubleshooting
First, place the affected Mac in DFU (device firmware update) mode using a connected host Mac. The DFU steps differ by Mac model. After the affected Mac enters DFU mode, revive or restore the firmware using either the Finder or Apple Configurator.
Note: The host Mac connects to the affected Mac in DFU mode with the application that’s frontmost when the affected Mac enters DFU mode. The other tool won’t show the affected Mac. To switch, close the application you don’t want to use.
Put a Mac laptop with Apple silicon in DFU mode
Connect the DFU port on the affected Mac to any USB-C port on the host Mac using a USB-C cable that supports both data and charging.
Note: Don’t connect anything else to the USB ports on the affected Mac during this process.
Hold the power button on the affected Mac for up to 10 seconds until it turns off.
Press and release the power button, then immediately hold all four of the following buttons at the same time:
Left Control ⌃
Left Option ⌥
Right Shift ⇧
Power button
Continue holding all four buttons for about 10 seconds, then release all buttons except the power button.
Hold the power button for up to 10 more seconds until the host Mac shows the Mac in DFU mode.
Note: Proper timing of key presses is important. If DFU mode doesn’t activate, disconnect the cable, hold the power button for 10 seconds to shut down the affected Mac, reconnect to the DFU port, and try again.
Put a Mac laptop with the T2 chip in DFU mode
Connect the DFU port on the affected Mac to any USB-C port on the host Mac using a USB-C cable that supports both data and charging.
Note: Don’t connect anything else to the USB ports on the affected Mac during this process.
Hold the power button on the affected Mac for up to 10 seconds until it turns off.
Press and release the power button, then immediately hold all four of the following buttons at the same time:
Left Control ⌃
Left Option ⌥
Right Shift ⇧
Power button
Continue holding all four buttons for about three seconds until the host Mac shows the Mac in DFU mode.
Note: Proper timing of key presses is important. If DFU mode doesn’t activate, disconnect the cable, hold the power button for 10 seconds to shut down the affected Mac, reconnect to the DFU port, and try again.
Put a Mac desktop in DFU mode
Connect the DFU port on the affected Mac to any USB-C port on the host Mac using a USB-C cable that supports both data and charging.
Note: Don’t connect anything else to the USB ports on the affected Mac during this process.
Unplug the affected Mac from its power source.
Press and hold the power button on the affected Mac.
While still holding the power button, plug the affected Mac back into power.
Continue holding the power button for up to 10 seconds until the host Mac shows the Mac in DFU mode.
Note: If DFU mode doesn’t activate, disconnect the cable, unplug the Mac from power, and try again.
If the Finder doesn’t show the Mac in DFU mode
What to look for:
The affected Mac doesn’t appear in the Finder sidebar on the host Mac after entering DFU mode.
The Finder doesn’t show the DFU window on the host Mac.
Steps to take:
In the Finder, choose Finder > Settings, click Sidebar, then make sure you select “CDs, DVDs, and iOS Devices.”
Check the Locations section of the Finder sidebar for Mac.
Disconnect the cable, hold the power button for 10 seconds to shut down the affected Mac, reconnect to the DFU port, and try again. Proper timing of key presses is important.
Confirm the USB-C cable supports both data and charging. Try a different USB-C cable.
Confirm that the host Mac has a reliable internet connection.
If the host Mac is on a managed network, confirm that the network permits traffic to
17.0.0.0/8.
Revive Mac firmware using the Finder
Put the affected Mac in DFU mode. See Put a Mac laptop with Apple silicon in DFU mode, Put a Mac laptop with the T2 chip in DFU mode, or Put a Mac desktop in DFU mode.
On the host Mac, open a Finder window. Select Mac in the sidebar, then select “Mac DFU Mode” on the right.
Click Revive Mac, then click Continue to confirm.
If prompted to update the macOS on the host Mac before continuing, do so before proceeding.
Wait while the Finder downloads the firmware and revives the Mac. The affected Mac restarts automatically when the revive completes.
If prompted on the affected Mac, select the volume to recover (such as Macintosh HD), then click Next.
If prompted, select a user and enter the login password, then click Next and restart.
For a Mac with Apple silicon, if startup options appear, select the startup disk, then click Continue.
Revive Mac firmware using Apple Configurator
Put the affected Mac in DFU mode. See Put a Mac laptop with Apple silicon in DFU mode, Put a Mac laptop with the T2 chip in DFU mode, or Put a Mac desktop in DFU mode.
On the host Mac, open Apple Configurator. The affected Mac in DFU mode appears in the Apple Configurator window.
Select the affected Mac, then choose Actions > Advanced > Revive Device. Confirm when prompted.
If prompted to update the macOS on the host Mac before continuing, do so before proceeding.
Wait while Apple Configurator downloads the firmware and revives the Mac. The affected Mac restarts automatically when the revive completes.
If prompted on the affected Mac, select the volume to recover (such as Macintosh HD), then click Next.
If prompted, select a user and enter the login password, then click Next and restart.
For a Mac with Apple silicon, if startup options appear, select the startup disk, then click Continue.
Restore Mac firmware using the Finder
WARNING: These steps erase the Mac and permanently delete all data. Confirm that a backup exists before following the steps below.
Put the affected Mac in DFU mode. See Put a Mac laptop with Apple silicon in DFU mode, Put a Mac laptop with the T2 chip in DFU mode, or Put a Mac desktop in DFU mode.
On the host Mac, open a Finder window. Select Mac in the sidebar, then select “Mac DFU Mode” on the right.
Click Restore Mac, then click Restore and Update to confirm.
If prompted to update the macOS on the host Mac before continuing, do so before proceeding.
Wait while the Finder downloads the firmware and restores the Mac. The affected Mac restarts automatically when the restore completes.
Restore Mac firmware using Apple Configurator
WARNING: These steps erase the Mac and permanently delete all data. Confirm that a backup exists before following the steps below.
Put the affected Mac in DFU mode. See Put a Mac laptop with Apple silicon in DFU mode, Put a Mac laptop with the T2 chip in DFU mode, or Put a Mac desktop in DFU mode.
On the host Mac, open Apple Configurator. The affected Mac in DFU mode appears in the Apple Configurator window.
Select the affected Mac, then choose Actions > Restore. Confirm when prompted.
If prompted to update the macOS on the host Mac before continuing, do so before proceeding.
Wait while Apple Configurator downloads the firmware and restores the Mac. The affected Mac restarts automatically when the restore completes.
After restoring Mac firmware
What happens after a restore depends on the chip in the Mac. On Apple silicon, the restore reinstalled macOS along with the firmware, so the Mac is ready for setup. On a Mac with the T2 chip, the restore reinstalled only the T2 firmware, so the user still needs to reinstall macOS through macOS Recovery.
Mac with Apple silicon:
The Mac prompts the user to sign in to the Apple Account previously associated with the Mac.
After signing in, complete setup using Setup Assistant.
Mac with the T2 chip:
The Mac starts up to a spinning globe, indicating macOS Recovery over the internet.
Choose a language, sign in to the Apple Account associated with the Mac, then click “Exit to Recovery.”
In macOS Recovery, select Reinstall macOS and follow the onscreen instructions.
After macOS installs, complete setup using Setup Assistant.
Managed environments
Device management may affect the outcome of firmware revive and restore.
Revive: A revive preserves data and settings, including device management enrollment and supervision. No reenrollment should occur after a successful revive.
Restore: A restore erases all content and settings. If the Mac uses Automated Device Enrollment (ADE), it reenrolls automatically during setup, provided the Mac has an assignment in Apple Business or Apple School Manager. Confirm the Mac has an assignment before performing a restore.
Activation Lock: If a device management service has turned on Activation Lock on the Mac, confirm with the device management administrator that they can clear it before performing a restore. A Mac with active Activation Lock may require additional steps to complete setup after a restore.