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I have a mid-2014 MBP that I tried to downgrade but unfortunately ended up wiping out everything in the hard disk.

Once it restarted, it doesn’t startup anymore and only the long press on [Option] after turning on is accessible. I have tried [Command + R], [Command+Option+Shift+R]… but it doesn’t work.

So On the only accessible menu I’ve found so far, I have access to {Internet Recovery} but it seems not working because I connected to the internet and waited 4 hours but nothing happened.

I considered using a usb boot but it doesn’t show up as an option, even though my other USB with no OS in it is detected by the Mac Startup Manager and displays a {windows} icon.

The USB is certainly not damaged since it’s recognized correctly when it doesn’t have the dmg installer.

Could somebody please help?

David Anderson
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papemoussa
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1 Answers1

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One possible answer would be to first install El Capitan, then upgrade to Catalina. The procedure is outlined below.

  1. Use the M1 Mac to download the El Capitan dmg file from the Apple website "How to get old versions of macOS".
  2. Use the M1 Mac to create a El Capitan USB flash drive installer. See the question: "How do I create El Capitan installer on a Catalina (or post-El Capitan) installed Mac for use on USB boot installer?".
  3. Use the flash drive to erase the disk on the 2014 MBP, then install El Capitan.
  4. Apply all updates to the installed El Capitan.
  5. Use the link provided on the Apple website "How to get old versions of macOS" to download Catalina from the App Store. If not available, then try to download to an older version of macOS such as High Sierra.
  6. Use the Install macOS Catalina application to upgrade to Catalina. If you downloaded an older version of macOS, then upgrade to the older version, then download and upgrade to Catalina.

Other References

David Anderson
  • 40,244