diff --git a/build_library/README.disk_layout b/build_library/README.disk_layout
index 9352a3b..cc2c990 100644
--- a/build_library/README.disk_layout
+++ b/build_library/README.disk_layout
@@ -107,7 +107,7 @@
         # (block_size * fs_blocks / 1024 / 1024 == MiB).
         "fs_size": "2048 MiB",
 
-        # Special handling of this partition. Expand is only supported value.
+        # Special handling of this partition.
         "features":["expand"],
 
         # Optional, default 'random'. Explicitly define the partition uuid.
@@ -207,6 +207,7 @@
 
 Features values:
   expand
+  last_partition
 
 
 
@@ -220,8 +221,9 @@
     images to be exactly large enough to hold files.
 
     On installation, its size will be expanded to use all available space
-    on the target drive. If it does not contain a valid file system, it will
-    be formatted to ext4 on system boot.
+    on the target drive, leaving room for a 'last_partition' if it exists.
+    If it does not contain a valid file system, it will be formatted on
+    system boot.
 
   Partition 2 - Kernel Slot A
     Contains the recovery kernel on recovery images. Contains the standard
@@ -259,6 +261,14 @@
     installation/update don't detect a secure bios (ie: ChromeOS hardware), then
     GRUB/UBoot, or other bios boot files/kernels will be installed here.
 
+  Partition 13 - MiniOS A (src/platform2/minios)
+    Partition at the beginning of disk. MiniOS A will have priority over
+    MiniOS B when booting.
+
+  Partition 14 - MiniOS B
+    Has feature 'last_partition' which ensures that it is placed at the
+    end of the disk.
+
 
 Inheritance Rules:
 
diff --git a/build_library/cgpt.py b/build_library/cgpt.py
index 1316abe..e4b2e1f 100755
--- a/build_library/cgpt.py
+++ b/build_library/cgpt.py
@@ -357,7 +357,7 @@
       'size', 'fs_size', 'fs_options', 'erase_block_size', 'hybrid_mbr',
       'reserved_erase_blocks', 'max_bad_erase_blocks', 'external_gpt',
       'page_size', 'size_min', 'fs_size_min'))
-  valid_features = set(('expand',))
+  valid_features = set(('expand', 'last_partition'))
 
   config = _LoadStackedPartitionConfig(filename)
   try:
@@ -541,6 +541,7 @@
   ret = {
       'expand_count': 0,
       'expand_min': 0,
+      'last_partition_count': 0,
       'byte_count': start_sector,
   }
 
@@ -559,6 +560,8 @@
       ret['expand_min'] += partition['bytes']
     else:
       ret['byte_count'] += partition['bytes']
+    if 'last_partition' in partition['features']:
+      ret['last_partition_count'] += 1
 
   # Account for the secondary GPT header and table.
   ret['byte_count'] += SECONDARY_GPT_BYTES
@@ -570,6 +573,11 @@
     raise InvalidLayout('1 expand partition allowed, %d requested'
                         % ret['expand_count'])
 
+  # Only one partition can be last on the disk.
+  if ret['last_partition_count'] > 1:
+    raise InvalidLayout('Only one last partition allowed, %d requested'
+                        % ret['last_partition_count'])
+
   # We lose some extra bytes from the alignment which are now not considered in
   # min_disk_size because partitions are aligned on the fly. Adding
   # fs_block_align_losses corrects for the loss.
@@ -805,6 +813,7 @@
 
   metadata = GetMetadataPartition(partitions)
   stateful = None
+  last_part = None
   # Set up the expanding partition size and write out all the cgpt add
   # commands.
   for partition in partitions:
@@ -816,6 +825,11 @@
       stateful = partition
       continue
 
+    # Save the last partition to place at the end of the disk..
+    if 'last_partition' in partition['features']:
+      last_part = partition
+      continue
+
     if (partition.get('type') in ['data', 'rootfs'] and partition['bytes'] > 1):
       lines += fs_align_snippet
 
@@ -842,7 +856,24 @@
     lines += fs_align_snippet + [
         'blocks=$(( numsecs - (curr + %d) / block_size ))' %
         SECONDARY_GPT_BYTES,
+    ]
+    if last_part is not None:
+      lines += [
+          'reserved_blocks=$(( (%s + block_size - 1) / block_size ))'
+          % last_part['var'],
+          ': $(( blocks = blocks - reserved_blocks ))',
+      ]
+    lines += [
         gpt_add % (stateful['num'], stateful['type'], stateful['label']),
+        ': $(( curr += blocks * block_size ))',
+    ]
+
+  if last_part is not None:
+    lines += [
+        'reserved_blocks=$(( (%s + block_size - 1) / block_size ))'
+        % last_part['var'],
+        'blocks=$((reserved_blocks))',
+        gpt_add % (last_part['num'], last_part['type'], last_part['label']),
     ]
 
   # Set default priorities and retry counter on kernel partitions.
diff --git a/build_library/minios_disk_layout.json b/build_library/minios_disk_layout.json
new file mode 100644
index 0000000..564cc9e
--- /dev/null
+++ b/build_library/minios_disk_layout.json
@@ -0,0 +1,30 @@
+{
+  # For MiniOS testing purposes only. Do not use.
+  "parent": "disk_layout_v2.json",
+  "metadata": {
+    "block_size": 512,
+    "fs_block_size": 4096,
+    "fs_align": "2 MiB"
+  },
+  "layouts": {
+    # common is the standard layout template.
+    "common": [
+      {
+        # MiniOS A partition.
+        "num": 13,
+        "label": "MiniOS-A",
+        "type": "kernel",
+        "size": "64 MiB"
+      },
+      {
+        # MiniOS B partition.
+        "num": 14,
+        "label": "MiniOS-B",
+        "type": "kernel",
+        "size": "64 MiB",
+        # Places partition at the end of disk.
+        "features": ["last_partition"]
+      }
+    ]
+  }
+}