Machines failing to boot post 10.15.4

[andrew_nicholas]

Has anyone else gotten reports of 2018/2019 TouchBar 15" machines failing to boot after installing 10.15.4? We've had two reports of this from different users across the country from one another, and both have reported the installers running then cutting to black and the machines being unresponsive. The users have reported not having additional peripherals installed nor forcing the machines to shut down. SMC resets and port/power outlet shuffle do not resolve anything.

[sdagley]

@andrew.nicholas During the 10.15.4 update process Macs with the T2 chip will also install a BridgeOS firmware update. As part of the update process the Mac turns itself off. If the user turns the Mac back on before the BridgeOS update completes and turns the Mac back on they may run into the problem that was seen with earlier updates where the drive encryption keys are wiped which renders internal storage unreadable.

[andrew_nicholas]

@sdagley Yea that was my worry. I asked the users if they had powered the device off at all before contacting our service desk fearing that and while they said no, I'm not so certain. The kicker is that the device just will not boot or power at all.

[sdagley]

@andrew.nicholas I had a 2018 MacBook Air that failed the same way when updating from Catalina 10.15.0 Beta 1 to Beta 2. I'm sure it's not what you want to hear, but I never got that machine working again and ended up having Apple replace it.

[andrew_nicholas]

@sdagley Yea it's pretty much what I expected, thanks for the feedback!

[sdagley]

@andrew.nicholas This might be worth trying: Revive firmware in Mac computers in Apple Configurator

[andrew_nicholas]

That did it, thank you sir!