While trying to recover and upgrade a FreeBSD install we ran into an issue where the kernel loader would hang when loading openzfs.ko:
linker_load_file: /boot/modules/openzfs.ko - unsupported file type
In this case
/boot/loader.conf had auto-importing enabled via this:
The default is 1, or disable auto import, since at least 2014 according to this commit. In this case there was a disk from another zpool put into the server and it was trying to auto-mount that but couldn’t due to it being broken.
Removing the line let us boot the server and clean it up.