A fresh change tucked away in the most recent macOS Sonoma beta could be a boon to Mac IT admins, as it should make it a little easier to get bricked Macs out of Device Firmware Update (DFU) mode.
Macs can get stuck in DFU mode for a handful of reasons, including when power fails during a software update installation. The problem is that once a Mac is stuck in that mode, it’s necessary to use a second Mac and Apple Configurator to get the machines going again.
In Sonoma, this is less of an issue because the relevant Configurator tools are now built into the Finder (though you will still need a second Mac to run the software).
USB-C cable still required
The good news is that connecting a second Mac to the bricked machine will no longer require you to download and install Configurator; you’ll only need a USB-C cable. Pop the cable into the rescue Mac and shut down the Mac you hope to bring back, then connect the cable to that second machine and follow the specific DFU instructions for your Mac, as detailed within this extensive Apple Support post.
As explained, while you must at the moment install Configurator to carry out the process, the latest beta changed that. A Twitter post reveals the change, citing a discovered Apple dialog note that states: “If you are experiencing problems with this Mac, you can attempt to revive it while preserving your media and other data by clicking Review Mac.”
If the process fails, then you’ll have no choice but to restore it to factory settings by clicking Restore Mac, which is why you should always backup your data.
Revive or Restore?
The difference between the two remedies follows:
Revive updates the firmware and updates the RecoveryOS to the latest volume. It doesn’t change any data, and the user/admin can then try to recover the Mac using RecoveryOS.
Restore updates firmware and RecoveryOS, but also returns the Mac to factory setting, which means all its data is destroyed.
In most cases, and for most users, you'll want the Revive command to succeed. No one enjoys the scent of lost data during deadline. Don’t forget that if you're working with Macs on a secured enterprise network, you must also ensure traffic from your devices to Apple’s web services are supported, as explained here.
More to come in Sonoma
This isn’t the only improvement macOS Sonoma provides Mac admins. The release holds a multitude of improvements around identity management, including extended use of Managed Apple IDs, federated identity, and the capacity to provision passcodes and passkeys automatically to managed IDs via iCloud Keychain. It also brings numerous security and privacy improvements to protect users and their systems.
Other enhancements include new tools for app and certificate deployment through Declarative Device Management and the capacity to force software updates on managed devices to take place at specific deadlines.
Automated device enrollment along with pester messages reminding users to engage in the process, along with Managed Device Attestation all make a big difference for IT. When used with device management systems such as those from Jamf, Kandji, and many other providers from across the Mac enterprise space, these tools make it easier to manage, provision, and secure Mac fleets. And now it's a little easier to get them working again if things go wrong, thanks to this latest improvement in DFU mode.
macOS Sonoma is currently available in both public and developer betas. The current assumption is that the new operating system will ship soon after the first M3 Macs are introduced in October.
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