Black Screen After MacBook Pro Update to macOS Big Sur
I had this happen to me on a late 2019 MacBook Pro as well, but dramatically worse: the machine was totally unresponsive, no chimes, no power up, nothing. I tried everything, including the usual PRAM clear and whatever else, but Apple suggested a replacement machine.<p>Since I can’t work because I’m waiting for the replacement,  I started tinkering to see what I could do and it turns out that the T2 security chip was totally nuked – the weird version of iOS it runs (BridgeOS) was broken&#x2F;missing, which means the hardware won’t even power on, POST, or light up the screen to tell you. Without the T2, you don’t have a computer anymore, basically.<p>Turns out that this chip <i>can</i> be flashed by using a specific set of incantations: <a href="https:&#x2F;&#x2F;support.apple.com&#x2F;en-ca&#x2F;guide&#x2F;apple-configurator-2&#x2F;apdebea5be51&#x2F;mac" rel="nofollow">https:&#x2F;&#x2F;support.apple.com&#x2F;en-ca&#x2F;guide&#x2F;apple-configurator-2&#x2F;a...</a><p>So, here’s what I had to do:<p>1. You need another Mac running the exact same build of the OS on the dead machine. I begrudgingly needed to update my Mac Mini to Big Sur to get it to work.<p>2. Plug a USB-C cable into the front left port of your dead MacBook, fire up Apple configurator on the functional machine and click “Revive.”<p>3. Wait, hope it works.... but there’s no confirmation so you just have to wait a long time and hope it was long enough, then hold the power button for 30 seconds to see if it’ll turn on.<p>4. If that doesn’t work (it didn’t), then you should run “restore” which is exactly the same. Wait a long time, hold the power button for 30 seconds and hope. Eventually, in my case, it powered up into internet recovery, and acted as if it were a new Mac. Everything is gone, but it’s at least functional as far as I can tell.<p>This will ONLY apply to the T2 models, which are not the ones mentioned in the OP, but it seems like a similar issues. These steps at least revived my machine, but it was so obscure that even Apple support didn’t know about this, so ordered a replacement. I can’t be the only one to have run into this, but I’m pretty pissed that I blew two entire days trying to figure out what was going on.<p>More details on my Twitter: <a href="https:&#x2F;&#x2F;twitter.com&#x2F;ow&#x2F;status&#x2F;1328389544119513089?s=21" rel="nofollow">https:&#x2F;&#x2F;twitter.com&#x2F;ow&#x2F;status&#x2F;1328389544119513089?s=21</a>