32-bit Xenial PXEboot install w/ preseed.cfg ignores expert_recipe string

Code:

# Alteatively, you may specify a disk to partition. If the system has only
# one disk the installer will default to using that, but otherwise the device
# name must be given in traditional, non-devfs format (so e.g. /dev/sda
# and not e.g. /dev/discs/disc0/disc).
# For example, to use the first SCSI/SATA hard disk:
#d-i partman-auto/disk string /dev/sda
d-i partman-auto/disk string /dev/mmcblk0

# In addition, you'll need to specify the method to use.
# The presently available methods are:
# - regular: use the usual partition types for your architecture
# - lvm:     use LVM to partition the disk
# - crypto:  use LVM within an encrypted partition
d-i partman-auto/method string regular

d-i partman-auto/expert_recipe string                      
    root ::                                                
        12800 100 12800 ext4                               
            $primary{ } $bootable{ } method{ format }      
            format{ } use_filesystem{ } filesystem{ ext4 } 
            mountpoint{ / }                                
        .                                                  
        12800 100 12800 ext4                               
            $primary{ } $bootable{ } method {format}       
            format{ } use_filesystem{ } filesystem{ ext4 } 
            mountpoint{ /alt-root }                        
        .                                                  
        6452 100 6452 ext4                                 
            $primary{ } method {format} format{ }          
            use_filesystem{ } filesystem{ ext4 }           
            mountpoint{ /repo }                            
        .

d-i partman-auto/choose_recipe select root

partman-basicfilesystems        partman-basicfilesystems/no_swap        boolean false

# This makes partman automatically partition without confirmation, provided
# that you told it what to do using one of the methods above.
d-i partman-partitioning/confirm_write_new_label boolean true
d-i partman/choose_partition select finish
d-i partman/confirm boolean true
d-i partman/confirm_nooverwrite boolean true

## Controlling how partitions are mounted
# The default is to mount by UUID, but you can also choose "traditional" to
# use traditional device names, or "label" to try filesystem labels before
# falling back to UUIDs.
d-i partman/mount_style select traditional

grub-installer  grub-installer/force-efi-extra-removable        boolean false

Code:

Device         Boot    Start      End  Sectors  Size Id Type
/dev/mmcblk0p1 *        2048 53219327 53217280 25.4G 83 Linux
/dev/mmcblk0p2      53221374 61077503  7856130  3.8G  5 Extended
/dev/mmcblk0p5      53221376 61077503  7856128  3.8G 82 Linux swap / Solaris