Do you have an iMac Retina 5K 27-inch Late 2015? (iMac17,1)

Many users of iMac 17,1 models – described officially as the iMac Retina 5K 27-inch Late 2015 – have been unable to get those Macs to update their firmware. I’m hearing reports that this hasn’t changed with the latest updates. I’d therefore like to submit a report to Apple with as much information about this problem as I can gather.

Please respond, either in a comment below, or by email to me (h [dot] oakley [at] btconnect [dot] com) if your iMac 17,1 has been updated using any of:

  • macOS Catalina 10.15.4 update, released 24 March 2020,
  • macOS Mojave Security Update 2020-002, released 24 March 2020,
  • macOS High Sierra Security Update 2020-002, released 24 March 2020.

If you have updated your iMac 17,1 with one of those, please check its firmware version. This is reported by my free SilentKnight and LockRattler utilities, or you can read it in About This Mac / System Report… / Hardware Overview / Boot ROM Version.

Following any of those three updates, your iMac 17,1 should show the Boot ROM version as Please let me know which yours is, even if has been updated successfully. Please don’t give me versions for other models, or for those which haven’t had any of those three updates installed.

If there are sufficient users whose iMacs haven’t been updated even after these most recent updates, I will put together a report for Apple.

Thank you for your help. Please spread the link to this article so that I can collect as many responses as possible.