MP 1,1-5,1 Mac Pro 5,1 (with metal GPU) won't boot from external usb HDD

[knyght]

I created a USB boot drive to install Monterey on my mac pro 5,1 currently running Mojave with use of RX580 GPU. I also installed OpenCore so I do get a boot screen even though the OPTION way doesn't work.

Issue is I do not see the external HDD as an option on the boot screen. It is seen by the Mac in startup disk and it says it is bootable in Disk Utility. I have tried all the USB ports so that isn't the problem.

??

 

[Macschrauber]

Have you tried the space key when OpenCore bootpicker is displaying to get more options?

 

[knyght]

Have you tried the space key when OpenCore bootpicker is displaying to get more options?

Yes. That didn't work

 

[Macschrauber]

You tried the factory usb ports and _not_ a port on an USB3 PCIe card?

non_factory usb ports are not seen by OpenCore without more tweaking.

 

[knyght]

You tried the factory usb ports and _not_ a port on an USB3 PCIe card?

non_factory usb ports are not seen by OpenCore without more tweaking.

Yes. It’s plugged into the USB port on the front of the tower

 

[hwojtek]

Does the disk show up properly in MacOS?
Do you have the proper drivers (HfsPlus.efi, IIRC) installed in your Open Core EFI partition? (/EFI/OC/Drivers) and included them in config.plist?

 

[sfalatko]

How do you know that your external "boot drive" is really a "boot drive"? How did you create the Monterey install drive? Do you happen to have a Mac that supports Monterey to confirm the drive can boot?

Just trying to check off possible sources of issues.