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User profile for user: DMBP24
DMBP24 Author
User level: Level 1
16 points

Exclamation at startup on M1 Macbook Air

After openingthe Software Update pane my M1 MacBook Air presented the exclamation point with the link support.apple.com/mac/restore


I followed the instructions but the process failed.

Failed to restore device in recovery mode, libusbrestore error:21 [com.apple.MobileDevice.MobileRestore – 0x15 (21)]


I used a MacMini 2018 to run Configurator 2 Version 2.13.3 (5B55) with Big Sur 11.2.3

What can I do to restore the firmware and get it working again?

MacBook Air 13″, macOS 11.2

Posted on Mar 18, 2021 8:25 PM

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User profile for user: DMBP24
DMBP24 Author
User level: Level 1
16 points

Posted on Mar 23, 2021 1:35 PM

I figured out the issue. The notebook will appear in Apple Configurator 2 when connected properly. The notebook MUST be selected(highlighted) in the Configurator window BEFORE the special key sequence is enacted on the notebook. Then the notebook screen will go black and the DFU rectangle shows in Apple Configurator 2 Window. SELECT the DFU icon then choose revive ore restore. I probably won't be the only one to make this mistake, hopefully there will be an edit to the instructions.


Thanks to those who helped.

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User profile for user: DMBP24
DMBP24 Author
User level: Level 1
16 points

Mar 23, 2021 1:35 PM in response to DMBP24

I figured out the issue. The notebook will appear in Apple Configurator 2 when connected properly. The notebook MUST be selected(highlighted) in the Configurator window BEFORE the special key sequence is enacted on the notebook. Then the notebook screen will go black and the DFU rectangle shows in Apple Configurator 2 Window. SELECT the DFU icon then choose revive ore restore. I probably won't be the only one to make this mistake, hopefully there will be an edit to the instructions.


Thanks to those who helped.

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User profile for user: jdo_apple
jdo_apple
User level: Community Specialist

Mar 20, 2021 3:22 PM in response to DMBP24

Hello DMBP24,


Welcome to Apple Support Communities. We understand you need help with your M1 MacBook Air not starting up properly and you tried to recover it with Apple Configurator 2.


Follow the helpful guide here, which includes links to update Apple Configurator 2 if needed:


Revive or restore a Mac with Apple silicon with Apple Configurator 2


Have a good day.

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User profile for user: Encryptor5000
Encryptor5000
User level: Level 5
7,568 points

Mar 20, 2021 3:35 PM in response to DMBP24

Hi DMPB24,


In order to revive or restore your M1 MacBook Air, it must be in Device Firmware Upgrade (DFU) mode. Please follow these steps to put your MacBook Air in DFU mode (also linked by jdo_apple): Revive or restore a Mac with Apple silicon with Apple Configurator 2 - Apple Support


Given the error you received, it appears that your Mac might not have been in true DFU mode. When your MacBook Air is in DFU mode, the display will be completely blank, and nothing will appear on it. Additionally, on the helper Mac running Apple Configurator 2, you should see a large DFU rectangle, with the name "Apple Controller" beneath it.


Also, attempt a revive first. This tries to repair your Mac's firmware without losing any data. If you're forced to restore, unfortunately you will lose all data stored on your Mac.

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Exclamation at startup on M1 Macbook Air

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