Ok, I am able to install High Sierra using the dosdude1 patcher.
But reading on the forum I know I need to update the firmware in this Mac Pro 4,1 and try to get it to 5,1 level.
According to what I've read, I need to boot into a "clean" Mac OS install not one that's been patched, to be successful in updating the firmware.
I've tried to make bootable USB installs using the Apple Support instructions that are linked in several threads.
But that does not produce a bootable USB image. When I try to use that to boot, holding down the Option key, I only get a "question mark" on top of a folder.
I know the USB is good, because I can mount and view it on a MacBook Pro running Big Sur.
Any ideas on what to do?
But reading on the forum I know I need to update the firmware in this Mac Pro 4,1 and try to get it to 5,1 level.
According to what I've read, I need to boot into a "clean" Mac OS install not one that's been patched, to be successful in updating the firmware.
I've tried to make bootable USB installs using the Apple Support instructions that are linked in several threads.
Create a bootable installer for macOS - Apple Support
You can use a USB flash drive or other secondary volume as a startup disk from which to install the Mac operating system. These steps are primarily for system administrators and other experienced users who are familiar with entering commands in Terminal.
support.apple.com
But that does not produce a bootable USB image. When I try to use that to boot, holding down the Option key, I only get a "question mark" on top of a folder.
I know the USB is good, because I can mount and view it on a MacBook Pro running Big Sur.
Any ideas on what to do?
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