iMac Intel 21.5" EMC 2805 Looping chime on booting 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;

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


Notes: 


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
I finally fixed my imac. Here is steps:


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


I founded solution and similar situation from here.