Thursday, September 12, 2019 [Tweets] [Favorites]

How to Restore BridgeOS on Your T2 Mac

Mr. Macintosh (tweet):

This article will go over how to restore BridgeOS on your T2 Mac. This is not something that you will ever normally have to do. Restoring or reinstalling BridgeOS would only be needed in the following situations.

  • 1. Failed macOS Upgrade
  • 2. Failed macOS Combo or Delta Update
  • 3. Failed macOS Security Update
  • 4. Failed macOS Reinstall
  • 5. Command Option R fails to boot your T2 Mac to the current version of macOS Recovery. (10.14 is out but the Mac boots to 10.13)

[…]

I tested the BridgeOS restore on multiple Macs for this article. One of my test devices failed in fantastic fashion. What I thought happened was the BridgeOS update just failed on a fluke. What really happened was Apple Configurator 2 attempted to downgrade BridgeOS from Catalina’s version down to the Production version of Mojave. When Apple Configurator 2 attempted to downgrade on the 3rd step it failed leaving the Mac in a Unusable state. Apple straight up does not allow downgrading BridgeOS. I still have my Air that does not boot.

So if you can’t downgrade, and Apple Configurator won’t let you restore the current (beta) version, I guess you’re just out of luck if you need to do this after installing a macOS beta.

See also: Howard Oakley.

Previously:

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