Will HS change my imac's firmware?

Discussion in 'macOS High Sierra (10.13)' started by stradify, Oct 3, 2017.

  1. stradify macrumors member

    Joined:
    Jul 4, 2015
    Location:
    USA
    #1
    Will trying out HSierra on an external usb ssd clone of my imac's hard drive result in a change to the firmware on the imac when I boot into it? Is there an option to keep the firmware the same? The reason I ask is this is a production machine so I don't want to find out that it no longer works properly with El Capitan when I reboot back into ElCap after trying out HSierra.
     
  2. Bubalight macrumors member

    Joined:
    Apr 22, 2015
    #2
    Yes, it will update your firmware if you install it directly.
    It is possible to run HSierra without the new firmware as long as you use a drive that is not APFS. If you have or can be loaned access to another mac that can install it, You can install onto the USB drive and the other Mac will get it's firmware updated but once its installed, it wont try to update again and you can move the USB drive to try it on the production iMac.
     
  3. h9826790 macrumors G5

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #3
    The new firmware only add APFS booting ability to your Mac, it will NOT affect it's ability to boot any OS that work with your current firmware.

    For someone like us still running Mac Pro 5,1. We can even boot 10.6.8 (Snow Leopard) with the new firmware.
     
  4. stradify thread starter macrumors member

    Joined:
    Jul 4, 2015
    Location:
    USA
    #4
    Good to know h9....! I was thinking that the firmware that gets updated might just be in the ssd. Anyone know if that's the case?
     
  5. chrfr macrumors 604

    Joined:
    Jul 11, 2009
    #5
    No, it's not just the SSD. I'm not sure that the SSDs firmware gets updated at all with the installation of High Sierra. The operating system installer will not do anything to firmware on an external, 3rd party SSD.
     
  6. h9826790 macrumors G5

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #6
    The firmware is stored on your Mac's logic board. NOT on the SSD (or any other storage).

    Even internal SSD, the SSD's firmware is totally isolated and independent to the Mac's firmware. I am 99% sure this OS firmware update won't touch the SSD's firmware.
     

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5 October 3, 2017