pfSense

Installing Plus 23.09.1 or CE 2.7.2 to a ZFS mirror does not format or populate the EFI partition on the additional disks of the mirror. Only the first disk in the mirror has a populated EFI filesystem with the expected loader files.

The EFI Partition for the second disk (or later) is created and labeled as /dev/gpt/efiboot1 (and so on) but there is no filesystem on that partition (and thus, no files).

Should the first disk in the mirror fail, this would leave the system unbootable.

Can be worked around by manually creating and populating the additional EFI partition(s) post-install

For example, to format and populate the EFI filesystem on the second disk of the mirror:

# newfs_msdos -F 32 -c 1 -L EFISYS1 /dev/gpt/efiboot1
# mount_msdosfs /dev/gpt/efiboot1 /mnt
# cp -R /boot/efi/ /mnt
# umount /mnt