I recently had to replace a drive in a zroot pool. I had to dig around to find the correct procedure for setting up the UEFI partition on the new drive so I thought I'd post what I had to do here. I had to piece this together from various forum posts and this blog post.
Hope this helps.
Code:
# freebsd-version
12.0-RELEASE-p8
Just to be safe, I won't use real device names here. Replace EXISTING and NEW with the proper devices.
This is the layout I'm working with. This was a basic 12.0-RELEASE install.
# gpart show EXISTING
=> 40 15628053088 EXISTING GPT (7.3T)
40 409600 1 efi (200M)
409640 1024 2 freebsd-boot (512K)
410664 984 - free - (492K)
411648 4194304 3 freebsd-swap (2.0G)
4605952 15623446528 4 freebsd-zfs (7.3T)
15628052480 648 - free - (324K)
First copy the partition table from an existing drive to the new drive (assuming they are identical drives):
# gpart backup EXISTING | gpart restore NEW
Check the partition layout on the new drive to make sure it matches an existing drive:
# gpart show NEW
=> 40 15628053088 NEW GPT (7.3T)
40 409600 1 efi (200M)
409640 1024 2 freebsd-boot (512K)
410664 984 - free - (492K)
411648 4194304 3 freebsd-swap (2.0G)
4605952 15623446528 4 freebsd-zfs (7.3T)
15628052480 648 - free - (324K)
Set up the EFI partition:
# gpart bootcode -p /boot/boot1.efifat -i 1 NEW
NEW should now be formatted as FAT:
# file -s /dev/NEWp1
/dev/NEWp1: DOS/MBR boot sector...
You can mount it to be sure:
# mount -t msdosfs /dev/NEWp1 /mnt
# find /mnt
/mnt
/mnt/efi
/mnt/efi/boot
/mnt/efi/boot/BOOTx64.efi
/mnt/efi/boot/startup.nsh
# umount /mnt
Then set up the boot code on the freebsd-boot partition:
# gpart bootcode -b /boot/pmbr -p /boot/gptzfsboot -i 2 NEWHope this helps.