Explainer: The ‘bricked’ Mac

There’s nothing that puts greater fear into the heart of any user than the prospect of their computer being bricked. Yet this is a term you’ll never come across in support documentation. Is it then, like dragons and unicorns, just another myth?

Like so many other words we use, bricking means different things. According to Wikipedia, “the word ‘brick’, when used in reference to consumer electronics, describes an electronic device such as a mobile device, game console, or router that, due to corrupted firmware, a hardware problem, or other damage, can no longer function”. That article goes on to draw distinction between a hard and soft brick, both of which cover a multitude of causes and consequences. It’s a term which is more evocative and terrifying that it is useful.

For example, a power supply failure, including blowing an internal fuse, or logic board failure result in hard bricking, a failed firmware update in a T2 or M1 Mac can produce similar signs, and it’s unclear whether a boot loop kernel panic is considered bricking at all.

As far as Macs are concerned, the key here may be “consumer electronics”. For try as Apple’s marketing department might like, any computer which ships with apps like Disk Utility and Terminal can hardly be deemed to fall in the same class as a ‘smart’ TV or even an iPhone. Macs are designed from the outset to be maintained and usually fixed by their users and support folk like system administrators. They’re definitely not black boxes which just work, as we have all experienced. However much a Mac user may defer maintenance and troubleshooting to others, consumer electronics they’re not.

So, if we’re to be more precise in our terminology, what should we distinguish?

First is the Mac which seems dead, with no signs of life at all, a completely black display, no startup sound, and no sign of lighting its power/status light or keyboard backlight. Here, the cause could be anything from failure to get mains power supply into the Mac, to a serious hardware failure. As it won’t start up in any mode, there’s nothing you can do once you’ve ruled out the obvious and easily remedied causes. This isn’t bricked, it’s dead.

Next is the Mac which shows minimal signs of life, but doesn’t appear to be making any serious effort at starting up: the power light, even the display, are on, but no one seems to be at home. While there are plenty of hardware causes for this, we now have three additional means of investigation: Recovery mode, hardware Diagnostics, and DFU mode. Force shutdown, if necessary, pick one of those, set your Mac up for it, and give it a go.

You’re likely to be unfamiliar with DFU mode, which is available on Intel Macs with T2 chips, and all Apple Silicon models. It’s only of use if you have a second, relatively recent Mac with Apple Configurator 2 installed, and a USB-C charging cable to connect the two back to back. If you don’t have those, or don’t want to try to recover your Mac yourself, then you’ll need to take or send it to an Apple store or authorised service provider, who should be happy to do this free of charge.

Apple explains exactly how to engage DFU mode and either revive or restore these Macs in Configurator’s Help book. Those articles are also available here for T2 Macs, and here for M1 series models. Although this may seem daunting the first time you do it, it’s actually no big deal at all. However, if your Intel Mac doesn’t have a T2 chip there’s no way to do this, and you may well need to get it seen at an Apple store or service provider.

If your Mac starts to boot and then hits problems, you need to observe carefully exactly what’s happening. If it only gets so far then restarts, in a seemingly endless boot cycle, that’s most probably a kernel panic occurring before the login screen – the dreaded boot loop. The best way ahead is to press and hold the Power button to force the Mac to shut down, then consider the way ahead. If your Mac won’t complete booting normally, then the same three options – Recovery mode, hardware Diagnostics, and DFU mode – are the only ones open.

However, before trying any of them you should prepare your Mac and peripherals to give them the best chance of success. Disconnect everything apart from bare essentials. If you normally start up from an external disk, it may be worth attaching that, as a missing boot disk can sometimes lead to a boot loop.

It’s also essential that you have time to approach the problem methodically and without getting panicked or flustered. If that moment isn’t now, leave your Mac shut down and return to it when you have got the time to tackle this properly.

Perhaps if we all stopped panicking over these problems and moved on from referring to them as bricking, they’d cease being dragons that we have to slay.