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iOS devices have DFU mode, which enable one to completely reinstall the firmware and operating system.

Do MacBook devices have something similar? Is the firmware automatically reinstalled upon an OS reinstallation?

Allan
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Max Savin
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2 Answers2

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Do MacBook devices have something [firmware] similar?

Yes. It's call the EFI or Extensible Firmware Interface

Is it possible to reinstall MacBook firmware?

Yes. See this post: Where is the EFI stored on the macbook and is it possible to restore a previous EFI firmware version?

Is the firmware automatically reinstalled upon an OS reinstallation?

Not necessarily. The EFI is upgraded only if it needs to be upgraded. This can happen as part of a normal update process or it can happen as part of a macOS installation.

From Apple Support:

Most firmware updates are automatically installed when you update or upgrade OS X. Some firmware updates are also available as downloads you can install manually. If your Mac needs a firmware update and it isn't installed automatically, check to see if a manual updater is listed below.

For the record - upgrade is defined as going from one version of macOS/OS X to the next one up.

It also goes on to state (which they highlight) the following:

If you don't see a firmware version listed in this article, it means that either a firmware update is only available as an automatic update, or no firmware update is needed.

Allan
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  • The response about reinstalling MacBook firmware could be inaccurate because Apple no longer ships firmware CDs. The answer in reference was from 2013. There is evidence that Apple changed how this works after in models that shipped after 2013. – Max Savin Jul 17 '17 at 13:43
  • DVD or USB flash is the same thing - it's just DVD has fallen out of favor. However, you can create a DVD based install which would include whatever firmware updates that would be required: https://apple.stackexchange.com/questions/235243/installing-el-capitan-from-a-bootable-dvd – Allan Jul 17 '17 at 16:19
  • Firmware updates are not the same as reinstallation.. – Max Savin Jul 18 '17 at 13:21
  • Oy vey... Please explain how you interpret the very last sentence of my answer. – Allan Jul 18 '17 at 14:14
  • Ah, previous Mac's shipped with an OS installation and a Firmware installation disk. Apple now does OS installation over the internet or USB, but they kind of killed the firmware part. I called Apple support about this and their top person did not know how it works on new models... I am waiting/hoping to hear back from their engineers now. – Max Savin Jul 18 '17 at 20:02
  • I updated my answer with info directly from Apple. The folks you spoke to weren't "engineers" by any stretch - they are techs - and you definitely didn't speak to their "top one." Their "best" techs are reserved assigned accounts . – Allan Jul 19 '17 at 00:21
  • Again, you missed the core of the question: Is it possible to reinstall MacBook firmware? The question you referenced refers to updating old models. You could tell because the Apple support page they reference has not been updated for many years. You might want to look into iPhone DFU mode you get what I am saying. – Max Savin Jul 20 '17 at 08:55
  • What makes you assume that an Intel EFI based computer has suddenly changed the way the EFI firmware is flashed is suddenly different because it's 1) older, and 2) an unrelated device using a different architecture does it a different way? If the info is wrong, then *you should indicate that you tried it and determined that it doesn't work*, not assume it's incorrect because it applies to "older models." – Allan Jul 20 '17 at 16:04
  • I have tried it: I went to the Apple's service center and called Apple Support seeking ways to reflash firmware, they both indicated that there is no download or documentation for the new models. Apple service said all they can do is reinstall the OS. However, they could not verify if reinstalling the OS reinstalls the firmware. Apple support opened a ticket for their engineering team, I'm currently waiting to hear back. – Max Savin Jul 25 '17 at 13:46
  • Additionally, if you look at EFI removal, it's possible on some older models but not the newer models. There was also a vulnerability a few years ago, to which Apple indicated models released after 2013 are not affected. Finally, Apple has a team working on EFI after the Thunderstrike vulnerability was publicized. So, it's reasonable to assume things are constantly changing. – Max Savin Jul 25 '17 at 13:56
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You can use DFU mode with macbooks too via Apple Configurator to either revive or restore a mac, but it's only supported on macs with a T2 chip (ie, Intel/M1/M2 macbooks made since 2018).

❗️The key combinations and timings can be very tricky to get right on first try (your fingers might hurt from the number of attempts you'll have to make).

See:

A few important points to keep in mind:

  1. The USB-C connecting cable can only go into one specific USB-C slot on the mac you want to revive/restore (indicated in the Apple page).
  2. Apple Configurator must be started after you have connected the cable.
  3. The Configurator will download an IPSW file from Apple servers and roll it out, but you can also provide a custom IPSW file manually downloaded e.g. from https://ipsw.me/product/Mac (only models that appear in the list support DFU mode).
ccpizza
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