Or you use the existing app in /Applications/Utilities if you happen to have it already. with unpkg) and locate the Firmware in the correspoding app. But it also might not and break something! If you’re unsure, go seek competent help at an Apple Store, from a Certified Apple Technician or some other professional!ĭownload the EFI Firmware update from Apple, unpack the package (e.g. It worked for me, it might work for you as well. I’m not responsible for anything that may happen if you continue reading and apply the next paragraph. On word of WARNING in the beginning: Don’t do anything described here if you don’t know what you’re doing. So, you find yourself in the need to flash an EFI update by hand on a mac? That’s awesome, I was in the same situation! My story is quite funny, it all started….nah, just kidding! First things first, I’ll tell you my story afterwards.