diff --git a/tools/releasetools/blockimgdiff.py b/tools/releasetools/blockimgdiff.py
index 199783d..c7a9e2b 100644
--- a/tools/releasetools/blockimgdiff.py
+++ b/tools/releasetools/blockimgdiff.py
@@ -297,7 +297,6 @@
     out = []
 
     total = 0
-    performs_read = False
 
     stashes = {}
     stashed_blocks = 0
@@ -415,7 +414,6 @@
         out.append("%s %s\n" % (xf.style, xf.tgt_ranges.to_string_raw()))
         total += tgt_size
       elif xf.style == "move":
-        performs_read = True
         assert xf.tgt_ranges
         assert xf.src_ranges.size() == tgt_size
         if xf.src_ranges != xf.tgt_ranges:
@@ -440,7 +438,6 @@
                 xf.tgt_ranges.to_string_raw(), src_str))
           total += tgt_size
       elif xf.style in ("bsdiff", "imgdiff"):
-        performs_read = True
         assert xf.tgt_ranges
         assert xf.src_ranges
         if self.version == 1:
@@ -551,6 +548,7 @@
     max_allowed = cache_size * stash_threshold / self.tgt.blocksize
 
     stashed_blocks = 0
+    new_blocks = 0
 
     # Now go through all the commands. Compute the required stash size on the
     # fly. If a command requires excess stash than available, it deletes the
@@ -566,8 +564,7 @@
           # that will use this stash and replace the command with "new".
           use_cmd = stashes[idx][2]
           replaced_cmds.append(use_cmd)
-          print("  %s replaced due to an explicit stash of %d blocks." % (
-              use_cmd, sr.size()))
+          print("%10d  %9s  %s" % (sr.size(), "explicit", use_cmd))
         else:
           stashed_blocks += sr.size()
 
@@ -582,8 +579,7 @@
         if xf.src_ranges.overlaps(xf.tgt_ranges):
           if stashed_blocks + xf.src_ranges.size() > max_allowed:
             replaced_cmds.append(xf)
-            print("  %s replaced due to an implicit stash of %d blocks." % (
-                xf, xf.src_ranges.size()))
+            print("%10d  %9s  %s" % (xf.src_ranges.size(), "implicit", xf))
 
       # Replace the commands in replaced_cmds with "new"s.
       for cmd in replaced_cmds:
@@ -593,9 +589,13 @@
           def_cmd = stashes[idx][1]
           assert (idx, sr) in def_cmd.stash_before
           def_cmd.stash_before.remove((idx, sr))
+          new_blocks += sr.size()
 
         cmd.ConvertToNew()
 
+    print("  Total %d blocks are packed as new blocks due to insufficient "
+          "cache size." % (new_blocks,))
+
   def ComputePatches(self, prefix):
     print("Reticulating splines...")
     diff_q = []
@@ -951,6 +951,57 @@
           a.goes_after[b] = size
 
   def FindTransfers(self):
+    """Parse the file_map to generate all the transfers."""
+
+    def AddTransfer(tgt_name, src_name, tgt_ranges, src_ranges, style, by_id,
+                    split=False):
+      """Wrapper function for adding a Transfer().
+
+      For BBOTA v3, we need to stash source blocks for resumable feature.
+      However, with the growth of file size and the shrink of the cache
+      partition source blocks are too large to be stashed. If a file occupies
+      too many blocks (greater than MAX_BLOCKS_PER_DIFF_TRANSFER), we split it
+      into smaller pieces by getting multiple Transfer()s.
+
+      The downside is that after splitting, we can no longer use imgdiff but
+      only bsdiff."""
+
+      MAX_BLOCKS_PER_DIFF_TRANSFER = 1024
+
+      # We care about diff transfers only.
+      if style != "diff" or not split:
+        Transfer(tgt_name, src_name, tgt_ranges, src_ranges, style, by_id)
+        return
+
+      # Change nothing for small files.
+      if (tgt_ranges.size() <= MAX_BLOCKS_PER_DIFF_TRANSFER and
+          src_ranges.size() <= MAX_BLOCKS_PER_DIFF_TRANSFER):
+        Transfer(tgt_name, src_name, tgt_ranges, src_ranges, style, by_id)
+        return
+
+      pieces = 0
+      while (tgt_ranges.size() > MAX_BLOCKS_PER_DIFF_TRANSFER and
+             src_ranges.size() > MAX_BLOCKS_PER_DIFF_TRANSFER):
+        tgt_split_name = "%s-%d" % (tgt_name, pieces)
+        src_split_name = "%s-%d" % (src_name, pieces)
+        tgt_first = tgt_ranges.first(MAX_BLOCKS_PER_DIFF_TRANSFER)
+        src_first = src_ranges.first(MAX_BLOCKS_PER_DIFF_TRANSFER)
+        Transfer(tgt_split_name, src_split_name, tgt_first, src_first, style,
+                 by_id)
+
+        tgt_ranges = tgt_ranges.subtract(tgt_first)
+        src_ranges = src_ranges.subtract(src_first)
+        pieces += 1
+
+      # Handle remaining blocks.
+      if tgt_ranges.size() or src_ranges.size():
+        # Must be both non-empty.
+        assert tgt_ranges.size() and src_ranges.size()
+        tgt_split_name = "%s-%d" % (tgt_name, pieces)
+        src_split_name = "%s-%d" % (src_name, pieces)
+        Transfer(tgt_split_name, src_split_name, tgt_ranges, src_ranges, style,
+                 by_id)
+
     empty = RangeSet()
     for tgt_fn, tgt_ranges in self.tgt.file_map.items():
       if tgt_fn == "__ZERO":
@@ -958,28 +1009,28 @@
         # in any file and that are filled with zeros.  We have a
         # special transfer style for zero blocks.
         src_ranges = self.src.file_map.get("__ZERO", empty)
-        Transfer(tgt_fn, "__ZERO", tgt_ranges, src_ranges,
-                 "zero", self.transfers)
+        AddTransfer(tgt_fn, "__ZERO", tgt_ranges, src_ranges,
+                    "zero", self.transfers)
         continue
 
       elif tgt_fn == "__COPY":
         # "__COPY" domain includes all the blocks not contained in any
         # file and that need to be copied unconditionally to the target.
-        Transfer(tgt_fn, None, tgt_ranges, empty, "new", self.transfers)
+        AddTransfer(tgt_fn, None, tgt_ranges, empty, "new", self.transfers)
         continue
 
       elif tgt_fn in self.src.file_map:
         # Look for an exact pathname match in the source.
-        Transfer(tgt_fn, tgt_fn, tgt_ranges, self.src.file_map[tgt_fn],
-                 "diff", self.transfers)
+        AddTransfer(tgt_fn, tgt_fn, tgt_ranges, self.src.file_map[tgt_fn],
+                    "diff", self.transfers, self.version >= 3)
         continue
 
       b = os.path.basename(tgt_fn)
       if b in self.src_basenames:
         # Look for an exact basename match in the source.
         src_fn = self.src_basenames[b]
-        Transfer(tgt_fn, src_fn, tgt_ranges, self.src.file_map[src_fn],
-                 "diff", self.transfers)
+        AddTransfer(tgt_fn, src_fn, tgt_ranges, self.src.file_map[src_fn],
+                    "diff", self.transfers, self.version >= 3)
         continue
 
       b = re.sub("[0-9]+", "#", b)
@@ -989,11 +1040,11 @@
         # for .so files that contain version numbers in the filename
         # that get bumped.)
         src_fn = self.src_numpatterns[b]
-        Transfer(tgt_fn, src_fn, tgt_ranges, self.src.file_map[src_fn],
-                 "diff", self.transfers)
+        AddTransfer(tgt_fn, src_fn, tgt_ranges, self.src.file_map[src_fn],
+                    "diff", self.transfers, self.version >= 3)
         continue
 
-      Transfer(tgt_fn, None, tgt_ranges, empty, "new", self.transfers)
+      AddTransfer(tgt_fn, None, tgt_ranges, empty, "new", self.transfers)
 
   def AbbreviateSourceNames(self):
     for k in self.src.file_map.keys():