I just updated my Mojave machine to Security Update 2020-006 but my bridgeOS has not updated, it remains on 18P50347c which I got when I tried Big Sur DP4/PB1 on 7 August 2020?

I don't have any other Macs so "downgrading (from beta to release) bridgeOS using Apple Configurator 2" isn't an option.

How can I get the latest bridgeOS on my Mojave Mac mini?

  • Are you upgrading or downgrading? Both words are in the body make it slightly confusing.
    – bmike
    Nov 16, 2020 at 17:23
  • 2
    Also, I feel I’m starting to belong to a Dell / Windows hobby club worrying about firmware . . . eclecticlight.co/2020/11/16/…
    – bmike
    Nov 16, 2020 at 17:49
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    I want to move from the beta bridgeOS I have to the release version. The "downgrade" process will do this once the latest release version is newer than the one you have. I agree it's ridiculous and confusing and I'm disappointed it is even something I need to do. That's New Apple, I guess. Nov 17, 2020 at 12:23

2 Answers 2


Due to the fact that you have previously installed a beta release, it looks like the bridgeOS update is skipped. Try to install the latest macOS Big Sur 11.0.1 (20B29) release on a external drive.

  • I don't have a suitable external drive (this Mac mini originally had Big Sur beta on it before I flattened and reverted back to Mojave) but will try to get a drive with 35GB free (I have a spare 32GB SSD, which is annoying). Nov 20, 2020 at 13:59

I have had decent success downloading the full installer. Usually that works without going to recovery but sometimes that is easier for people. But I only go to newer bridge, not regress so you might need someone to hack together a regression step if the full installer doesn’t get your the briegeOS you seek.

Your process is the same to retry an install if Big Sur (or any oter upgrade) fails.

softwareupdate --fetch-full-installer --full-installer-version 10.14.6

Or you could go to the Mojave install page:

  • this command doesn't work, it just shows me the softwareupdate help text. google says it was introduced in Catalina. Nov 17, 2020 at 19:09
  • Mojave download and install via App Store link did not update it — in fact it took me back to a system pre Security Update 2020-005! Urgh, a lot of re-upgrading to do. Nov 18, 2020 at 0:08
  • Yeah, sometimes the full installer lags. You may be waiting for the next major release cycle, unfortunately @MattSephton
    – bmike
    Nov 18, 2020 at 0:12

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