I am trying to Factory Restore iPhone 6S "A1633" on my Mac Running Big Sur 11.1 / Intel.

I am in recovery mode on the phone and plug it in it starts the update OR restore downloads the file, installs then produces this error. It seems that the firmware file from apple is corrupt in some way.

The iPhone “iPhone” could not be restored because the firmware file was corrupt.

Disconnect and reconnect, then try again.

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1 Answer 1


Throw the file out & try again.

It's stored in ~/Library/iTunes/iPhone Software Updates/

  • It's empty, apple seems to delete the download after you make an attempt each time, and it downloads it each time you try to update as well. Feb 2, 2021 at 16:33
  • 1
    OK. I've never tried this for restore so idk how it will present to you, but for update it will let you download as a separate act, which does leave the file in there (I do this frequently as my partner & I have identical phones, so one download, then just copy over to her mac). My guess is that it's deleting it because it's corrupt, rather than because you used it to restore. Another idea - ISPs don't seem to cache files like they used to, but if you reboot all your network hardware, router, hubs, wifi, Mac, then try again, hopefully any version badly-cached on its way to you will be flushed.
    – Tetsujin
    Feb 2, 2021 at 16:41

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