Boot failure / Looping chime on boot? - Logic board or EFI problem?
yesterday I accidentally installed the boot-loader "Clover" on the EFI partition of my MacBook Pro (Mid 2012 - A1398).
From that point on, the Macbook booted into Clover and not my normal system. I was able to choose to boot into Recovery Mode, so I had access to the hard drive again. Then I decided to rename the folder /EFI/CLOVER/ into /EFI/CLOVER-OLD in an attempt to disable Clover.
But now i have big trouble because my Macbook won't boot anymore at all. The screen stays completely black and the keyboard does not work as well. I cannot boot into Recovery Mode nor can I reset the NVRAM or SMC, etc. The keyboard simply doesn't respond. The only thing that happens is that the startup sound ("chime") is playing constantly in a loop when i turn it on :(
So its no power issue, the Macbook is still reacting to the On/Off button but boot doesn't work.
I have already removed the SSD drive, but the issue is still there regardless of the hard drive being connected or not..
I really don't know what I can do ?
I think it is the logic board, right ? Can I repair this issue by replacing the EFI BIOS Rom Chip / EFI firmware or something like that ? Would be very grateful for your advice !