The macOS Monterey 12.3 update, released this week, renders Macs with replaced logic boards unusable, causing panic among users who are unable to get their devices to work. This has led to a flood of reports on social media and Apple's support forums.
Notably, Apple this week released macOS Monterey 12.3, which, among other features, brought Universal Control to users. Unfortunately, not all users can experience Universal Control or the latest software update.
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As reported on Apple's developer forum, users trying to update their Mac to macOS 12.3 from macOS 12.2.1 (or earlier) are experiencing errors, endless reboots, and possibly a bricked Mac. The reports are limited to Macs that have had their logic boards replaced, specifically the new 14-inch and 16-inch MacBook Pros.
More specifically, it is reported that there is a firmware bug in Mac OS 12.3 that makes it impossible to install the update on any 2021 14- or 16-inch MacBook Pro that has had its logic board replaced.
The only way to fix the device is to download the 12.2.1 IPSW and use Apple Configurator 2, with the Mac in DFU mode, to load the revive image. This will update the iBoot firmware, and the recovery image to a working version. The device will then restore to macOS 12.2.1 while preserving your data.
According to reports, there are two possible outcomes that users may face. Either the Mac is corrupted and cannot be used, or the Mac completes the update process and restarts but ultimately fails to update and displays the iBoot Panic message.
A Reddit thread from users reports similar issues. One user reported that when trying to upgrade to macOS version 12.3 on a 2021 M1 14-inch MacBook, the entire download and upgrade process completes, but when it restarts, it appears to still be on version 12.2.1.
If the Mac doesn't turn on after the upgrade process, users will need to put it into DFU mode and manually restore it. This process, however, requires users to have a second compatible Mac to restore their bricked Mac. Of course, since many users only have one Mac or no Mac compatible with Apple Configurator, they resort to the Apple Store for help.
Even a visit to the Apple Store will result in the staff replacing the already faulty logic board with another one, putting users through a never-ending process until the error is fixed. Users are reporting what they are facing when trying to put their device into DFU mode. One Reddit user shared some tips:
❝Any attempts to download macOS version 12.3 to your Mac will fail due to the error.
However, you should be able to enter DFU mode. You should wait until the exclamation mark appears and then press the key sequence to enter DFU. The Configurator will let you try to revive it in recovery mode but I'm not sure if that will work. I assume this is error 21. If you try in DFU mode you will get error 2006.
The second time I attempted a regular system upgrade, the screen refused to show anything as a result of the firmware failure – but it showed up in Configurator and the key sequence for DFU continued to work.❞
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There are also reports on the MacRumors forum with one user describing being unable to install version 12.3 in any way: direct upgrade, installation via the App Store, Recovery mode, and DFU restore have all failed. The user is forced to download the IPSW for version 12.2 in order to use it.
Apple seems to offer some instructions on how to revive an Apple Silicon here , and you can also find instructions for Intel-based Macs here.
Source: macrumors.com
