Don't think its the 8GB that's causing this - I've encountered this 'copy of apfs.efi failed' message many times - solution is to initially erase the USB key carefully - I have found Disk Utility is not reliable - ERASE and PARTITION processes (in 10.12) are not clear and certainly not fully functioning - instead use terminal command (see other posts for details).. Then use EFI Mounter v3 app to see if you can mount the USB key's EFI folder - usually this also indicates that Unibeast will complete the install.. good luck on next steps!"There was an error creating your UniBeast drive: Copy of apfs.efi failed."
Installing High Sierra ver 10.13.2 to 8GB memory stick, using UEFI mode.
Any recommendations? Is 16GB really necessary? 8GB worked with Mavericks
What is the chance that UniBeast will support X299+Skylake-X eventually now that the SMBIOS iMacPro1,1 is out in the wild?
I know there is a great guide for installation of High Sierra on X299, but I would really love a UniBeast to get as much as possible to work out of the box before attempting this project.
A FakeCPUID is necessary for x299 using UniBeast. Modify your config plist to include one and UniBeast should work. Check out this post for details: