diff --git a/tools/releasetools/edify_generator.py b/tools/releasetools/edify_generator.py
index a5340a0..7978062 100644
--- a/tools/releasetools/edify_generator.py
+++ b/tools/releasetools/edify_generator.py
@@ -305,7 +305,7 @@
     if input_path is None:
       data = input_zip.read("OTA/bin/updater")
     else:
-      data = open(os.path.join(input_path, "updater")).read()
+      data = open(input_path, "rb").read()
     common.ZipWriteStr(output_zip, "META-INF/com/google/android/update-binary",
                        data, perms=0755)
 
diff --git a/tools/releasetools/ota_from_target_files b/tools/releasetools/ota_from_target_files
index 1afc640..a7936b1 100755
--- a/tools/releasetools/ota_from_target_files
+++ b/tools/releasetools/ota_from_target_files
@@ -21,7 +21,7 @@
 
 Usage:  ota_from_target_files [flags] input_target_files output_ota_package
 
-  -b  (--board_config)  <file>
+  --board_config  <file>
       Deprecated.
 
   -k (--package_key) <key> Key to use to sign the package (default is
@@ -62,6 +62,11 @@
       file-based OTA if the target_files is older and doesn't support
       block-based OTAs.
 
+  -b  (--binary)  <file>
+      Use the given binary as the update-binary in the output package,
+      instead of the binary in the build's target_files.  Use for
+      development only.
+
 """
 
 import sys
@@ -103,6 +108,7 @@
 OPTIONS.two_step = False
 OPTIONS.no_signing = False
 OPTIONS.block_based = False
+OPTIONS.updater_binary = None
 
 def MostPopularKey(d, default):
   """Given a dict, return the key corresponding to the largest
@@ -507,7 +513,7 @@
 endif;
 endif;
 """ % bcb_dev)
-  script.AddToZip(input_zip, output_zip)
+  script.AddToZip(input_zip, output_zip, input_path=OPTIONS.updater_binary)
   WriteMetadata(metadata, output_zip)
 
 def WritePolicyConfig(file_context, output_zip):
@@ -748,7 +754,7 @@
 """ % bcb_dev)
 
   script.SetProgress(1)
-  script.AddToZip(target_zip, output_zip)
+  script.AddToZip(target_zip, output_zip, input_path=OPTIONS.updater_binary)
   WriteMetadata(metadata, output_zip)
 
 def WriteIncrementalOTAPackage(target_zip, source_zip, output_zip):
@@ -1127,14 +1133,14 @@
 endif;
 """ % bcb_dev)
 
-  script.AddToZip(target_zip, output_zip)
+  script.AddToZip(target_zip, output_zip, input_path=OPTIONS.updater_binary)
   WriteMetadata(metadata, output_zip)
 
 
 def main(argv):
 
   def option_handler(o, a):
-    if o in ("-b", "--board_config"):
+    if o == "--board_config":
       pass   # deprecated
     elif o in ("-k", "--package_key"):
       OPTIONS.package_key = a
@@ -1159,6 +1165,8 @@
       OPTIONS.no_signing = True
     elif o == "--block":
       OPTIONS.block_based = True
+    elif o in ("-b", "--binary"):
+      OPTIONS.updater_binary = a
     else:
       return False
     return True
@@ -1176,6 +1184,7 @@
                                               "two_step",
                                               "no_signing",
                                               "block",
+                                              "binary=",
                                               ],
                              extra_option_handler=option_handler)