Chip de firmware BIOS EFI: A1311 Apple iMac 21,5" i5 2,5 GHz mediados de 2011 MC309LL/A
This chip has to be soldered on board. (1) to fix a corrupt (bricked) EFI firmware bios chip. (2) to remove EFI firmware pass-word (i t will NOT remove the OS pass-word). (Chip to be soldered on board).