Create encrypted geli zpool against single disk on FreeBSD 10.3

zfs_geli_boot.sh

#/bin/sh                                                                                                                                              
                                                                                                                                                      
# Create partitions                                                                                                                                   
gpart destroy -F /dev/ada0                                                                                                                            
gpart create -s GPT /dev/ada0                                                                                                                         
gpart add -t efi -s 100M -a 1M -l EFI /dev/ada0                                                                                                       
gpart add -t freebsd-swap -s 8G -a 1M -l freebsd-swap /dev/ada0                                                                                       
gpart add -t freebsd-ufs -s 10G -a 1M -l freebsd-ufsboot /dev/ada0                                                                                    
gpart add -t freebsd-zfs -a 1M -l freebsd-zfsgeli /dev/ada0                                                                                           
                                                                                                                                                      
# UEFI Configure                                                                                                                                      
newfs_msdos -F 16 -L FreeBSD_EFI /dev/ada0p1                                                                                                          
mkdir /tmp/efi                                                                                                                                        
mount -t msdosfs /dev/ada0p1 /tmp/efi                                                                                                                 
mkdir -p /tmp/efi/EFI/BOOT                                                                                                                            
cp /boot/boot1.efi /tmp/efi/EFI/BOOT/BOOTX64.EFI                                                                                                      
umount /dev/ada0p1                                                                                                                                    
                                                                                                                                                      
# UFS Boot partition                                                                                                                                  
newfs -L ufsboot -S 4096 /dev/ada0p3                                                                                                                  
mkdir /tmp/ufsboot                                                                                                                                    
mount /dev/ada0p3 /tmp/ufsboot                                                                                                                        
                                                                                                                                                      
# Enable AES                                                                                                                                          
kldload aesni                                                                                                                                         
                                                                                                                                                      
# Geli stuff                                                                                                                                          
mkdir -p /tmp/ufsboot/boot/geli                                                                                                                       
chmod 750 /tmp/ufsboot/boot/geli                                                                                                                      
dd if=/dev/random of=/tmp/ufsboot/boot/geli/ada0p4.key bs=64 count=1                                                                                  
chmod 640 /tmp/ufsboot/boot/geli/ada0p4.key                                                                                                           
geli init -e AES-XTS -l 128 -s 4096 -b -K /tmp/ufsboot/boot/geli/ada0p4.key /dev/ada0p4                                                               
cp /var/backups/ada0p4.eli /tmp/ufsboot/boot/geli/                                                                                                    
geli attach -k /tmp/ufsboot/boot/geli/ada0p4.key /dev/ada0p4                                                                                          
                                                                                                                                                      
# ZFS                                                                                                                                                 
zpool create -R /mnt -O canmount=off -O mountpoint=none -O atime=off -O compression=lz4 zroot /dev/ada0p4.eli                                         
                                                                                                                                                      
# Container for boot environments:                                                                                                                    
zfs create -o canmount=off -o mountpoint=none zroot/ROOT                                                                                              
                                                                                                                                                      
# Default boot environment:
zfs create -o mountpoint=/ zroot/ROOT/master                                                                                                          
                                                                                                                                                      
# Things we want to be unique for each boot environment:                                                                                              
zfs create -o mountpoint=/usr/jails zroot/ROOT/master/jails                                                                                           
zfs create -o mountpoint=/usr/local zroot/ROOT/master/local                                                                                           
zfs create -o mountpoint=/usr/ports zroot/ROOT/master/ports                                                                                           
zfs create -o mountpoint=/var zroot/ROOT/master/var                                                                                                   
zfs create -o mountpoint=/var/log zroot/ROOT/master/log                                                                                               
                                                                                                                                                      
# Things we want to be common across boot environments:                                                                                               
zfs create -o mountpoint=/usr/home zroot/home                                                                                                         
zfs create -o mountpoint=/usr/obj zroot/obj                                                                                                           
zfs create -o mountpoint=/usr/ports/distfiles zroot/distfiles                                                                                         
zfs create -o mountpoint=/usr/src zroot/src                                                                                                           
zfs create -o mountpoint=/tmp zroot/tmp                                                                                                               
zfs create -o mountpoint=/var/tmp zroot/vartmp                                                                                                        
                                                                                                                                                      
# Setup boot                                                                                                                                          
umount /dev/ada0p3                                                                                                                                    
mkdir /mnt/ufsboot                                                                                                                                    
mount /dev/ada0p3 /mnt/ufsboot                                                                                                                        
                                                                                                                                                      
echo "Installing FreeBSD!"                                                                                                                            
cd /mnt                                                                                                                                               
for i in base kernel ; do \                                                                                                                           
  tar -xf /usr/freebsd-dist/${i}.txz -C .                                                                                                             
done                                                                                                                                                  
                                                                                                                                                      
cp -a boot/* ufsboot/boot/                                                                                                                            
rm -rf boot                                                                                                                                           
ln -s ufsboot/boot boot                                                                                                                               
                                                                                                                                                      
cat << EOF > /mnt/etc/fstab                                                                                                                           
# Device   Mountpoint   FStype   Options   Dump   Pass#                                                                                               
/dev/ada0p2.eli   none   swap   sw,ealgo=AES-XTS,keylen=128,sectorsize=4096   0   0                                                                   
/dev/ada0p3   /ufsboot   ufs   rw   1   1                                                                                                             
EOF
cat << EOF > /mnt/boot/loader.conf                                                                                                                    
aesni_load="YES"                                                                                                                                      
geom_eli_load="YES"                                                                                                                                   
geli_ada0p4_keyfile0_load="YES"                                                                                                                       
geli_ada0p4_keyfile0_type="ada0p4:geli_keyfile0"                                                                                                      
geli_ada0p4_keyfile0_name="/boot/geli/ada0p4.key"                                                                                                     
zfs_load="YES"                                                                                                                                        
vfs.root.mountfrom="zfs:zroot/ROOT/master"                                                                                                            
EOF                                                                                                                                                   
                                                                                                                                                      
cat << EOF > /mnt/etc/rc.conf                                                                                                                         
zfs_enable="YES"                                                                                                                                      
EOF