MP 7,1 Apple changes DFU software for Intel T2 Macs

[Regulus67]

I am struggling to restore one iMac Pro after having upgraded the SSD pair. Even after updating to macOs: Sonoma 14.7.4 on a mac mini M1.

Apple is no longer using the Apple Configurator app to revive or restore desktop macs.

https://support.apple.com/en-us/108900
Published Date: February 18, 2025

What you need to revive or restore​

1. The affected Mac, which is the ... Mac with the Apple T2 Security Chip that you're reviving or restoring. Other Mac models don't apply.
2. Another Mac of any model using macOS Sonoma 14 or later. You will use this Mac to revive or restore the affected Mac.
3. ...

Instead using , DFU window in Finder
And it's interesting to see how the desktop mac is presented. A desktop mac is now an iOS handheld device?

 

[kitKAC]

The configurator app still works. Also, where do you see a desktop Mac being presented as an iOS device in those screenshots?

 

[Regulus67]

The configurator app still works. Also, where do you see a desktop Mac being presented as an iOS device in those screenshots?

I don't know, the Configurator app does not work in my case. It starts installing the software, but the progress bar didn't move and then after 5 mins, it would show the other mac had disconnected from DFU mode.

The last screenshot. I did not use an iPhone for this process at all

 

[mattspace]

Continuing to be a clown show for a process that should be done from an iPhone plugged into the dead machine.

 

[Regulus67]

Continuing to be a clown show for a process that should be done from an iPhone plugged into the dead machine.

Yes. Apple seems to force updated firmware on T2 macs. And only offer the latest supported macOS with internet recovery.
Moving toward the same procedure as iPhones? Where Apple will only sign the latest iOS installed, with no option to go back to an older version

 

[mattspace]

Yes. Apple seems to force updated firmware on T2 macs. And only offer the latest supported macOS with internet recovery.
Moving toward the same procedure as iPhones? Where Apple will only sign the latest iOS installed, with no option to go back to an older version

I thought internet recovery could install the version of the OS the machine originally shipped with?

 

[Regulus67]

I thought internet recovery could install the version of the OS the machine originally shipped with?

It used to. But I also were not able to do it on my Mac Pro 2019 June last year, remember? Was forced to install macOS Sonoma (2023).

https://forums.macrumors.com/threads/install-macos-on-new-ssd-kit.2429259/

But I had no problem installing macOS Monterey (2021) in June 2023, so something has changed after Sonoma was released.

Unless someone has been able to install older macOS on a mac with T2 chip without any problems using internet recovery? After Sonoma was released

edit: one can download an older macOS and install using a USB stick, after having made changes to boot-up security.
But the mac has to already have a functional macOS installed. Using DFU Restore mode wipes the mac, and prevents changing boot security

 

[mattspace]

Unless someone has been able to install older macOS on a mac with T2 chip without any problems using internet recovery? After Sonoma was released

Just to clarify this didn't work?

However, starting up with Command + Option + R keys in Internet Recovery Mode will automatically upgrade your Mac to the latest compatible macOS. The other set of key combinations (Command + Shift + Option + R) will download the version of macOS that was factory-preloaded on your Mac in Internet Recovery.

The second key combo didn't work to get you back to the originally shipped OS version?

 

[Regulus67]

The second key combo didn't work to get you back to the originally shipped OS version?

Correct

 

[chrfr]

I don't know, the Configurator app does not work in my case. It starts installing the software, but the progress bar didn't move and then after 5 mins, it would show the other mac had disconnected from DFU mode.

The last screenshot. I did not use an iPhone for this process at all

DFU restores on T2 Macs don’t fully install macOS. DFU restores only install the T2 firmware. You still need to do internet recovery to get macOS on the computer after the restore. By contrast, a DFU restores on an Apple Silicon Mac does fully install macOS.

 

[Regulus67]

DFU restores on T2 Macs don’t fully install macOS. DFU restores only install the T2 firmware. You still need to do internet recovery to get macOS on the computer after the restore. By contrast, a DFU restores on an Apple Silicon Mac does fully install macOS.

I know. DFU Restore mode installs BridgeOS and lock the new SSDs to the T2. After successfully installing that, it will restart and Internet Recovery will start.

How to Restore BridgeOS on a T2 Mac + Boot a Mac to DFU Mode

macOS Update brick your Mac? This article will show you how boot to DFU Mode and restore BridgeOS on a T2 MacBook Pro, Air, iMac Pro, Mac Mini & Mac Pro!

mrmacintosh.com

My present attempt is described in this thread

https://forums.macrumors.com/threads/imac-pro-will-not-start-after-rebuild.2449503/