diff --git a/tools/releasetools/blockimgdiff.py b/tools/releasetools/blockimgdiff.py
index 72f065d..8b6a690 100644
--- a/tools/releasetools/blockimgdiff.py
+++ b/tools/releasetools/blockimgdiff.py
@@ -1558,6 +1558,7 @@
     split_large_apks = []
     cache_size = common.OPTIONS.cache_size
     split_threshold = 0.125
+    assert cache_size is not None
     max_blocks_per_transfer = int(cache_size * split_threshold /
                                   self.tgt.blocksize)
     empty = RangeSet()
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index 2b04334..9f48f78 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -848,12 +848,13 @@
 def LoadRecoveryFSTab(read_helper, fstab_version, recovery_fstab_path,
                       system_root_image=False):
   class Partition(object):
-    def __init__(self, mount_point, fs_type, device, length, context):
+    def __init__(self, mount_point, fs_type, device, length, context, slotselect):
       self.mount_point = mount_point
       self.fs_type = fs_type
       self.device = device
       self.length = length
       self.context = context
+      self.slotselect = slotselect
 
   try:
     data = read_helper(recovery_fstab_path)
@@ -881,10 +882,13 @@
 
     # It's a good line, parse it.
     length = 0
+    slotselect = False
     options = options.split(",")
     for i in options:
       if i.startswith("length="):
         length = int(i[7:])
+      elif i == "slotselect":
+        slotselect = True
       else:
         # Ignore all unknown options in the unified fstab.
         continue
@@ -898,7 +902,8 @@
 
     mount_point = pieces[1]
     d[mount_point] = Partition(mount_point=mount_point, fs_type=pieces[2],
-                               device=pieces[0], length=length, context=context)
+                               device=pieces[0], length=length, context=context,
+                               slotselect=slotselect)
 
   # / is used for the system mount point when the root directory is included in
   # system. Other areas assume system is always at "/system" so point /system
@@ -913,7 +918,8 @@
   """Finds the path to recovery fstab and loads its contents."""
   # recovery fstab is only meaningful when installing an update via recovery
   # (i.e. non-A/B OTA). Skip loading fstab if device used A/B OTA.
-  if info_dict.get('ab_update') == 'true':
+  if info_dict.get('ab_update') == 'true' and \
+     info_dict.get("allow_non_ab") != "true":
     return None
 
   # We changed recovery.fstab path in Q, from ../RAMDISK/etc/recovery.fstab to
diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py
index ad001d1..16d7485 100755
--- a/tools/releasetools/ota_from_target_files.py
+++ b/tools/releasetools/ota_from_target_files.py
@@ -78,6 +78,13 @@
       Write a copy of the metadata to a separate file. Therefore, users can
       read the post build fingerprint without extracting the OTA package.
 
+  --force_non_ab
+      This flag can only be set on an A/B device that also supports non-A/B
+      updates. Implies --two_step.
+      If set, generate that non-A/B update package.
+      If not set, generates A/B package for A/B device and non-A/B package for
+      non-A/B device.
+
 Non-A/B OTA specific options
 
   -b  (--binary) <file>
@@ -251,6 +258,7 @@
 OPTIONS.output_metadata_path = None
 OPTIONS.disable_fec_computation = False
 OPTIONS.boot_variable_values = None
+OPTIONS.force_non_ab = False
 
 
 METADATA_NAME = 'META-INF/com/android/metadata'
@@ -933,7 +941,7 @@
           'ro.build.version.security_patch'),
   }
 
-  if target_info.is_ab:
+  if target_info.is_ab and not OPTIONS.force_non_ab:
     metadata['ota-type'] = 'AB'
     metadata['ota-required-cache'] = '0'
   else:
@@ -2067,6 +2075,8 @@
       OPTIONS.output_metadata_path = a
     elif o == "--disable_fec_computation":
       OPTIONS.disable_fec_computation = True
+    elif o == "--force_non_ab":
+      OPTIONS.force_non_ab = True
     else:
       return False
     return True
@@ -2103,6 +2113,7 @@
                                  "skip_compatibility_check",
                                  "output_metadata_path=",
                                  "disable_fec_computation",
+                                 "force_non_ab",
                              ], extra_option_handler=option_handler)
 
   if len(args) != 2:
@@ -2164,11 +2175,17 @@
     OPTIONS.skip_postinstall = True
 
   ab_update = OPTIONS.info_dict.get("ab_update") == "true"
+  allow_non_ab = OPTIONS.info_dict.get("allow_non_ab") == "true"
+  if OPTIONS.force_non_ab:
+    assert allow_non_ab, "--force_non_ab only allowed on devices that supports non-A/B"
+    assert ab_update, "--force_non_ab only allowed on A/B devices"
+
+  generate_ab = not OPTIONS.force_non_ab and ab_update
 
   # Use the default key to sign the package if not specified with package_key.
   # package_keys are needed on ab_updates, so always define them if an
-  # ab_update is getting created.
-  if not OPTIONS.no_signing or ab_update:
+  # A/B update is getting created.
+  if not OPTIONS.no_signing or generate_ab:
     if OPTIONS.package_key is None:
       OPTIONS.package_key = OPTIONS.info_dict.get(
           "default_system_dev_certificate",
@@ -2176,7 +2193,7 @@
     # Get signing keys
     OPTIONS.key_passwords = common.GetKeyPasswords([OPTIONS.package_key])
 
-  if ab_update:
+  if generate_ab:
     GenerateAbOtaPackage(
         target_file=args[0],
         output_file=args[1],