This was a huge help. I’m still on Sierra but updated Clover to the latest because...well...I don’t know why I did, it was all working perfectly fine before the update. I was kicking myself for hours because I have an entire backup startup drive in my machine and arrogantly updated Clover on both before rebooting the first and confirming success. Took most of the day to fix.
I think there is a bug in the Clover install that overlooks that file on some machines. If you customize the Clover install, which I never considered before yesterday, you can see it’s still there and available.
A more convenient solution to a potential Unlucky Clover issue is to have a backup boot device, even one with an old system/Clover installation. I (now) have a very old 16GB SSD in a USB enclosure lying around that easily holds a basic Unibeast installation and a working older version of Clover. That enables me to get to the Clover boot screen, and from there to choose the usual MacOS boot volume, and from there to use the usual Clover and EFI manipulation tools to troubleshoot the missing files...instead of tracking down typing all those long copy/cp commands. (So yeah, I now have two backup boot systems.)
I also discovered yesterday that the copy commands in that barebones Clover Shell absolutely do not work reliably. In my efforts yesterday trying to better understand the problem, and maybe due to some confusion as to which of my EFI drives was being summoned at boot by the NVRAM settings in the motherboard, I tried to copy the entire backup Clover to the working Clover installation in various ways. The Clover Shell cp command worked on individual small files, as you’ve explained it here, but stopped dead in its tracks, frozen solid, on any medium to large copy job whether that job was a single file or multiple files in a directory.
Very frustrating. There’s really no substitute for some kind of a backup boot device with a Hackintosh.