For the record, OP and I have talked at length over PM. She allegedly completed this guide correctly, but the Switch still refuses to boot. When I inspected a decrypted PRODINFO from HacDiskMount, I noticed it was corrupt.
We found a good backup of PRODINFO from when Atmosphere was used, but the above error occurs when trying to restore it.
I don't know what was done to screw up the Switch so badly, but I know I'm not getting the full story. I gave up.