Restoring PostgreSQL directory backups

PostgreSQL data files are (as we all know) version and platform specific.

I tried to recover some data from a backed up /var/lib/postgresql/9.4/main directory.

The system was originally a 32 bit Debian 9. I accidentally installed a 64 bit version of Debian 9 and got the error message

FATAL: incorrect checksum in control file

on startup. After deleting the VM and reinstalling the correct version of Linux (and PostgreSQL from PGDG), I could successfully restore the data directory and restore my data.