I am in trouble with my imac. Let me tell our story;

My imac was too slow and I decided to change HDD with a SSD. If I just be changed HDD, There was no problem. But I want to clone my HDD to SSD hard drive.

  • I cloned my HDD to SSD with follow this video. I used Carbon Copy Cloner app for clone, and I did something with Multibeast like in video(I guess problem start this point, I wish I had not Multibeast).
  • I changed HDD like this link
  • Open my Imac and came a boot screen I never seen ago; screen
  • I choose one but screen freezed, I waited for hours but there was no progress.
  • And I close Imac use power button.
  • Now my Imac looping chime on booting like this macbook


  • If I unplug Screen cable, Chime sound come only one and fan running.
  • I try thunderbolt output for display but not working.
  • I try PRAM reset not working, I removed PRAM battery even but not working.
  • I try reinstall macos with USB or direcly with HDD but not working.

I think Multibeast corrupted EFI Flash So I learned Multibeast using for Hackintosh after this incident.

How can I fix my Imac? If problem about with EFI Flash, How can I reinstall EFI on rom.

Thanks in advance

  • There's a few things here that still aren't clear. For example, when you say that reinstalling macOS with USB or a HDD doesn't work, can you explain why? What actually happens when you try? Also, when you say I try PRAM reset not working, do you mean that you couldn't reset the PRAM, or that resetting it didn't fix the problem? And what happens if you try the "Boot Mac OS X from USB" option at bottom of the screen? Finally, it'd be good to know if you have: (1) access to any other Macs and, if so, which models, (2) a current backup of your data (I assume so if you used Carbon Copy Cloner).
    – Monomeeth
    Apr 12, 2018 at 3:42
  • 1- Imac can't boot from USB or HDD, I tried keyboard shortcuts but I can't interrupt boot loop. 2- I tried PRAM reset with keyboard combination and I also removed PRAM battery for reset. 3- I am not want to save my data, I want to see apple logo on my Imac.
    – Savas Adar
    Apr 12, 2018 at 8:17
  • Okay, so, what happens if you power off your iMac and switch it back on and immediately hold down the Option+Command+R keys?
    – Monomeeth
    Apr 12, 2018 at 8:54
  • nothing happens
    – Savas Adar
    Apr 12, 2018 at 15:02

1 Answer 1


I finally fixed my imac. Here is steps:

  1. I bought a new EFI chip from https://macunlocks.com/
  2. I changed chip on mainboard my imac. chip on board
  3. Finally my mac was opened but lanuage was chinese and ask me efi password(new chip has no efi pass.)
  4. Reset PRAM with CMD + Alt + P + R how to reset PRAM
  5. Fixed! Imac living after 2 months later.

I founded solution and similar situation from here.

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