Author Topic: mountain lion requires 64bit EFI  (Read 724 times)

0 Members and 1 Guest are viewing this topic.

Offline chrisNova777

  • Administrator
  • Posts: 9092
  • Gender: Male
  • "Vintage MIDI Sequencing + Audio Production"
    • | vintage audio production software + hardware info
mountain lion requires 64bit EFI
« on: July 12, 2020, 06:47:23 PM »

On those older Mac Pros that shipped with unsupported graphics cards, Apple hasn't deigned to update their firmware to support 64-bit EFI. You can run this command in Terminal to see whether you have a 32-bit or 64-bit EFI:

ioreg -l -p IODeviceTree | grep firmware-abi

All of the Macs dropped by Mountain Lion are going to return "EFI32" - if you can hack around that in addition to upgrading your graphics card, you may indeed be able to get Mountain Lion running on an older Mac, but it's a bit of a long shot.