diff --git a/core/Makefile b/core/Makefile
index d309179..3b62f8b 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -823,6 +823,7 @@
 $(if $(BOARD_HAS_EXT4_RESERVED_BLOCKS),$(hide) echo "has_ext4_reserved_blocks=$(BOARD_HAS_EXT4_RESERVED_BLOCKS)" >> $(1))
 $(if $(BOARD_SYSTEMIMAGE_SQUASHFS_COMPRESSOR),$(hide) echo "system_squashfs_compressor=$(BOARD_SYSTEMIMAGE_SQUASHFS_COMPRESSOR)" >> $(1))
 $(if $(BOARD_SYSTEMIMAGE_SQUASHFS_COMPRESSOR_OPT),$(hide) echo "system_squashfs_compressor_opt=$(BOARD_SYSTEMIMAGE_SQUASHFS_COMPRESSOR_OPT)" >> $(1))
+$(if $(BOARD_SYSTEMIMAGE_SQUASHFS_DISABLE_4K_ALIGN),$(hide) echo "system_squashfs_disable_4k_align=$(BOARD_SYSTEMIMAGE_SQUASHFS_DISABLE_4K_ALIGN)" >> $(1))
 $(if $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_SYSTEM_BASE_FS_PATH),$(hide) echo "system_base_fs_file=$(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_SYSTEM_BASE_FS_PATH)" >> $(1))
 $(if $(BOARD_USERDATAIMAGE_FILE_SYSTEM_TYPE),$(hide) echo "userdata_fs_type=$(BOARD_USERDATAIMAGE_FILE_SYSTEM_TYPE)" >> $(1))
 $(if $(BOARD_USERDATAIMAGE_PARTITION_SIZE),$(hide) echo "userdata_size=$(BOARD_USERDATAIMAGE_PARTITION_SIZE)" >> $(1))
@@ -833,6 +834,7 @@
 $(if $(BOARD_VENDORIMAGE_JOURNAL_SIZE),$(hide) echo "vendor_journal_size=$(BOARD_VENDORIMAGE_JOURNAL_SIZE)" >> $(1))
 $(if $(BOARD_VENDORIMAGE_SQUASHFS_COMPRESSOR),$(hide) echo "vendor_squashfs_compressor=$(BOARD_VENDORIMAGE_SQUASHFS_COMPRESSOR)" >> $(1))
 $(if $(BOARD_VENDORIMAGE_SQUASHFS_COMPRESSOR_OPT),$(hide) echo "vendor_squashfs_compressor_opt=$(BOARD_VENDORIMAGE_SQUASHFS_COMPRESSOR_OPT)" >> $(1))
+$(if $(BOARD_VENDORIMAGE_SQUASHFS_DISABLE_4K_ALIGN),$(hide) echo "vendor_squashfs_disable_4k_align=$(BOARD_VENDORIMAGE_SQUASHFS_DISABLE_4K_ALIGN)" >> $(1))
 $(if $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_VENDOR_BASE_FS_PATH),$(hide) echo "vendor_base_fs_file=$(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_VENDOR_BASE_FS_PATH)" >> $(1))
 $(if $(BOARD_OEMIMAGE_PARTITION_SIZE),$(hide) echo "oem_size=$(BOARD_OEMIMAGE_PARTITION_SIZE)" >> $(1))
 $(if $(BOARD_OEMIMAGE_JOURNAL_SIZE),$(hide) echo "oem_journal_size=$(BOARD_OEMIMAGE_JOURNAL_SIZE)" >> $(1))
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index 856d3c2..5dffcac 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -113,7 +113,7 @@
   # Must be of the form "YYYY-MM-DD" on production devices.
   #
   # If there is no $PLATFORM_SECURITY_PATCH set, keep it empty.
-  PLATFORM_SECURITY_PATCH := 2016-07-05
+  PLATFORM_SECURITY_PATCH := 2016-08-05
 endif
 
 ifeq "" "$(PLATFORM_BASE_OS)"
diff --git a/tools/releasetools/blockimgdiff.py b/tools/releasetools/blockimgdiff.py
index 82d5397..66d5907 100644
--- a/tools/releasetools/blockimgdiff.py
+++ b/tools/releasetools/blockimgdiff.py
@@ -261,7 +261,8 @@
 # original image.
 
 class BlockImageDiff(object):
-  def __init__(self, tgt, src=None, threads=None, version=4):
+  def __init__(self, tgt, src=None, threads=None, version=4,
+               disable_imgdiff=False):
     if threads is None:
       threads = multiprocessing.cpu_count() // 2
       if threads == 0:
@@ -274,6 +275,7 @@
     self._max_stashed_size = 0
     self.touched_src_ranges = RangeSet()
     self.touched_src_sha1 = None
+    self.disable_imgdiff = disable_imgdiff
 
     assert version in (1, 2, 3, 4)
 
@@ -340,6 +342,21 @@
     return ctx.hexdigest()
 
   def WriteTransfers(self, prefix):
+    def WriteTransfersZero(out, to_zero):
+      """Limit the number of blocks in command zero to 1024 blocks.
+
+      This prevents the target size of one command from being too large; and
+      might help to avoid fsync errors on some devices."""
+
+      zero_blocks_limit = 1024
+      total = 0
+      while to_zero:
+        zero_blocks = to_zero.first(zero_blocks_limit)
+        out.append("zero %s\n" % (zero_blocks.to_string_raw(),))
+        total += zero_blocks.size()
+        to_zero = to_zero.subtract(zero_blocks)
+      return total
+
     out = []
 
     total = 0
@@ -521,9 +538,8 @@
       elif xf.style == "zero":
         assert xf.tgt_ranges
         to_zero = xf.tgt_ranges.subtract(xf.src_ranges)
-        if to_zero:
-          out.append("%s %s\n" % (xf.style, to_zero.to_string_raw()))
-          total += to_zero.size()
+        assert WriteTransfersZero(out, to_zero) == to_zero.size()
+        total += to_zero.size()
       else:
         raise ValueError("unknown transfer style '%s'\n" % xf.style)
 
@@ -552,7 +568,8 @@
 
     # Zero out extended blocks as a workaround for bug 20881595.
     if self.tgt.extended:
-      out.append("zero %s\n" % (self.tgt.extended.to_string_raw(),))
+      assert (WriteTransfersZero(out, self.tgt.extended) ==
+              self.tgt.extended.size())
       total += self.tgt.extended.size()
 
     # We erase all the blocks on the partition that a) don't contain useful
@@ -714,6 +731,7 @@
             # produces significantly smaller patches than bsdiff).
             # This is permissible if:
             #
+            #  - imgdiff is not disabled, and
             #  - the source and target files are monotonic (ie, the
             #    data is stored with blocks in increasing order), and
             #  - we haven't removed any blocks from the source set.
@@ -723,7 +741,7 @@
             # zip file (plus possibly extra zeros in the last block),
             # which is what imgdiff needs to operate.  (imgdiff is
             # fine with extra zeros at the end of the file.)
-            imgdiff = (xf.intact and
+            imgdiff = (not self.disable_imgdiff and xf.intact and
                        xf.tgt_name.split(".")[-1].lower()
                        in ("apk", "jar", "zip"))
             xf.style = "imgdiff" if imgdiff else "bsdiff"
diff --git a/tools/releasetools/build_image.py b/tools/releasetools/build_image.py
index 7247610..9ee472b 100755
--- a/tools/releasetools/build_image.py
+++ b/tools/releasetools/build_image.py
@@ -400,10 +400,14 @@
       build_command.extend(["-C", fs_config])
     if "selinux_fc" in prop_dict:
       build_command.extend(["-c", prop_dict["selinux_fc"]])
+    if "block_list" in prop_dict:
+      build_command.extend(["-B", prop_dict["block_list"]])
     if "squashfs_compressor" in prop_dict:
       build_command.extend(["-z", prop_dict["squashfs_compressor"]])
     if "squashfs_compressor_opt" in prop_dict:
       build_command.extend(["-zo", prop_dict["squashfs_compressor_opt"]])
+    if "squashfs_disable_4k_align" in prop_dict and prop_dict.get("squashfs_disable_4k_align") == "true":
+      build_command.extend(["-a"])
   elif fs_type.startswith("f2fs"):
     build_command = ["mkf2fsuserimg.sh"]
     build_command.extend([out_file, prop_dict["partition_size"]])
@@ -540,6 +544,7 @@
     copy_prop("has_ext4_reserved_blocks", "has_ext4_reserved_blocks")
     copy_prop("system_squashfs_compressor", "squashfs_compressor")
     copy_prop("system_squashfs_compressor_opt", "squashfs_compressor_opt")
+    copy_prop("system_squashfs_disable_4k_align", "squashfs_disable_4k_align")
     copy_prop("system_base_fs_file", "base_fs_file")
   elif mount_point == "data":
     # Copy the generic fs type first, override with specific one if available.
@@ -557,6 +562,7 @@
     copy_prop("has_ext4_reserved_blocks", "has_ext4_reserved_blocks")
     copy_prop("vendor_squashfs_compressor", "squashfs_compressor")
     copy_prop("vendor_squashfs_compressor_opt", "squashfs_compressor_opt")
+    copy_prop("vendor_squashfs_disable_4k_align", "squashfs_disable_4k_align")
     copy_prop("vendor_base_fs_file", "base_fs_file")
   elif mount_point == "oem":
     copy_prop("fs_type", "fs_type")
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index a47c78c..e589028 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -1440,11 +1440,12 @@
 
 class BlockDifference(object):
   def __init__(self, partition, tgt, src=None, check_first_block=False,
-               version=None):
+               version=None, disable_imgdiff=False):
     self.tgt = tgt
     self.src = src
     self.partition = partition
     self.check_first_block = check_first_block
+    self.disable_imgdiff = disable_imgdiff
 
     if version is None:
       version = 1
@@ -1455,7 +1456,8 @@
     self.version = version
 
     b = blockimgdiff.BlockImageDiff(tgt, src, threads=OPTIONS.worker_threads,
-                                    version=self.version)
+                                    version=self.version,
+                                    disable_imgdiff=self.disable_imgdiff)
     tmpdir = tempfile.mkdtemp()
     OPTIONS.tempfiles.append(tmpdir)
     self.path = os.path.join(tmpdir, partition)
diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py
index 3c9d14a..8649498 100755
--- a/tools/releasetools/ota_from_target_files.py
+++ b/tools/releasetools/ota_from_target_files.py
@@ -870,9 +870,15 @@
   # disk type is ext4
   system_partition = OPTIONS.source_info_dict["fstab"]["/system"]
   check_first_block = system_partition.fs_type == "ext4"
+  # Disable using imgdiff for squashfs. 'imgdiff -z' expects input files to be
+  # in zip formats. However with squashfs, a) all files are compressed in LZ4;
+  # b) the blocks listed in block map may not contain all the bytes for a given
+  # file (because they're rounded to be 4K-aligned).
+  disable_imgdiff = system_partition.fs_type == "squashfs"
   system_diff = common.BlockDifference("system", system_tgt, system_src,
                                        check_first_block,
-                                       version=blockimgdiff_version)
+                                       version=blockimgdiff_version,
+                                       disable_imgdiff=disable_imgdiff)
 
   if HasVendorPartition(target_zip):
     if not HasVendorPartition(source_zip):
@@ -886,9 +892,11 @@
     # disk type is ext4
     vendor_partition = OPTIONS.source_info_dict["fstab"]["/vendor"]
     check_first_block = vendor_partition.fs_type == "ext4"
+    disable_imgdiff = vendor_partition.fs_type == "squashfs"
     vendor_diff = common.BlockDifference("vendor", vendor_tgt, vendor_src,
                                          check_first_block,
-                                         version=blockimgdiff_version)
+                                         version=blockimgdiff_version,
+                                         disable_imgdiff=disable_imgdiff)
   else:
     vendor_diff = None