And I tried routedir=drive0/var/gpsapp/routes after making that directory, and it also worked.

And there was no /programs0 partition and even if there was, there was nothing in it?

See, my goal was to remove the need for /programs0 and preinit completely. So one of the things I made sure to do was to get rid of that partition (or at least make sure it wasn't mounted). At first I thought GPSapp was working in the new folder, until I realized I'd still left /programs0 lying around as-is. This all started going bad after I removed preinint and /programs0....