Won't boot afther upgrade to macOS Sierra
Hello I have a problem with my Imac 21,5" A1418 EMC 2544
I have upgraded From El Capitain to macOS Sierra.
After second restart it went i a boot loop with grey screen and boot chime over and over again.
I have disconnected my LCD and connected a external screen same thing .
When i boot up without internal or external screen connected no boot loop only 1 chime and then it runs high speed fan.
My question is how do i reset my NVRAM without screens and EFI password set ( I know the password set it my self ) .
Or can some one tel me what i can do about this or what part or parts i have to re-please so i have a working screen again .
Is this a good question?