Deleted member 188658
As explained i can work from this Yosemite hard drive and access the high sierra drive.
Please i need your help.
I had a similar problem some months ago. It turned out that I installed HS 10.13.2 with a HFS formatted drive, and then when I installed 10.13.4 it demanded a APFS formatted drive. So the install was APFS but Clover was missing the apfs.efi in DRIVERS64EFI. I booted from a USB stick, mounted the EFI partition and copied the correct apfs.efi to the SSD EFI partition.
I could then boot into new install.
But it seems like you may have covered that case....
Just a thought/suggestion