820-00923 in update loop

[apfelimperium]

Hello Community,

I have a liquid damaged 820-00923-A on my desk. After ultrasonic it always boots into an update OS. The updates ends with an error saying "A critical software update is required for your mac, but an error was encountered while installing this update."

• OS was already reinstalled without fixing the problem.
• Some forum say it is an WatchOS update for the touchbar. New touchbar did not fix the problem.

Does anybody know this issue? Any ideas where to look?

Thanks for you help!

 

[2informaticos]

Can you boot USB OSX?
Also try disconnecting Lifeboat connector.

 

[apfelimperium]

Booting USB OSX with or without connected lifeboat connector both ends in the same error