MP 1,1-5,1 Stuck on loading OCLP from internal EFI partition

[nowave7]

Hi all,

I just installed Big Sur (11.7.10) on mac pro 5,1 with OCLP (1.4.3) bundled in the installer. Everything went fine, the machine booted, and the OCLP detected that it booted from the USB, so it offered to build and install it to an internal driver, which I naturally did.
I shutdown the machine, took out the USB and then booted it back on, only to be stuck at the greyish screen.
After a new restart, this time holding the options key, I got into the boot picker where there were only two options present, the EFI and the Big Sur. Selecting the EFI makes the machine freeze, and nothing else works other than restarting it.
Any ideas what it could be? I'm thinking dirty EFI partition, but I'm unsure as to how to erase it?
Worth noting is that once the USB is back in the machine and selected as the boot option, the machine starts without any issue.
Thanks!

 

[nowave7]

Something else I tried, is to add another internal drive, and install OCLP onto it, but the end result is the same, it is just stuck at loading the EFI Boot.
Just as an illustration, here's a photo of what the problem looks like

 

[aj19876]

At initially boot, you said Open Core offered to install onto the SSD; it should have also prompted you to do root patching. The prompt may not have appeared for you, but you still need to manually do root patching.

If you want to access the EFI partition, you can do that via terminal:

GUIDE - How to Mount EFI Partition on macOS

How to Mount EFI Partition on macOS An EliteMacx86 Exclusive Guide - This guide covers mounting of EFI Partition on macOS using several methods. Method #1: Using Terminal Using this method, you don't need an app and can use Terminal which is available within macOS. To mount the EFI partition...

elitemacx86.com