MacOS: Reviving or Restoring with Mac DFU Mode (ETS Internal)

Summary

This article explains how to troubleshoot an Apple Mac computer with Apple Silicon or Apple T2 co-processor that is unable to boot properly to the main operating system or into internet recovery.

 

Content

When a Mac computer cannot boot properly, it will enter recovery mode where the user can repair the disk, re-install the OS, or make changes via the terminal command line interface. However, in rare circumstances, when the device has suffered a large failure in its' software, it may even fail to boot into recovery. When this happens, you can put the Mac computer into Device Firmware Update (DFU) mode to attempt rendering the device to a useable state. 

Image showing a Mac that needs to be recovered in DFU Mode:

Example of Mac screen when device needs to be recovered in DFU mode.

 

What is DFU Mode?

Device Firmware Update (DFU) mode is a low-level recovery mode that allows the user to reload the OS and update the firmware of the device with a specialized bootloader.

 

How-To

Task: To perform a revive or restore

When placing a Mac into DFU mode, the following options may be performed:

Revive: Uses a host Mac to copy an OS update to the problematic Mac computer while attempting to preserve user data.

Restore: Fully erases the problematic Mac computer and reinstalls the OS from a host Mac. 

A revive or restore may be warranted in the following scenarios:

  • Power failure interrupts a software update
  • Mac cannot boot into the recovery partition or internet recovery
  • Mac boots to a warning screen (i.e. exclamation point or missing folder icon)
  • Mac turns on but does not boot or show any video

Note: A revive or restore only applies to Macs with Apple Silicon (M Series) or Intel Macs with the T2 co-processor. This roughly includes most modern Macs from 2018 through 2024. If the Mac is older, use either internet recovery and or booting with Target Disk Mode . 

Use the Apple Serial Number Lookup Tool to see the age of your device

Instructions

Step 1 - Locate a host machine – This can be any Mac with Apple Silicon or T2 co-processor running macOS Sonoma or later. 

Step 2 - Connect the host machine and the machine to be revived/restored to power and make sure the host machine is connected to the internet. 

Step 3 - Using a USB C to USB C cable, connect both machines together using the left most USB C port on the device.

Example of where C-ports can be found on a Mac.

Image showing the DFU port on a Macbook Pro. On Macs without Magsafe (magnetic charger), the DFU port is the port on the left of the device closest to the display.

 

Important: Keep both Macs connected to power and connected to each other for the entire process below.

Step 4 - Open Finder on the host machine.

Step 5 - On the machine to be revived/restored, power it off fully then use the following keyboard command. 

  • Press the power button once to turn on the device
  • Simultaneously press and hold:
    •  left control ⌃
    •  left option ⌥
    •  right shift  ⇧
    •  power button

Keep holding all keys for about 10 seconds then release all keys except the power button. The device then should appear in the Finder window of the host device. Once the Mac appears on the host device, release the keys. 

Key combination examples on Mac.

Image showing keyboard combination to put Mac into DFU Mode.

 

Step 6 - Once the Mac is in DFU mode and appears in the Finder on the host device, you will see the option to revive or restore.  

Step 7 - Choose which operation you would like to perform and let the process run until completion. 

Important: Keep both macs connected to power and connected to each other for the entire process. 

 

Outcome

Following either of the recovery method above, the Mac should now be in a bootable, usable state that will allow the user to use the device.

 

Further Readings

Apple Support - How to revive or restore Mac firmware 

  • Use this article if you need to revive or restore a Mac desktop rather than a laptop

Apple Support - Apple Serial Number Lookup Tool 

Recover Mac Storage Drive Data via Target Disk Mode 

 

Need additional help?

Visit the Technology Help Desk Support page to locate your local campus contact information or to submit an online technology support request.  For password issues you must call or visit the Help Desk in person.  

 

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