diff --git a/tools/releasetools/add_img_to_target_files.py b/tools/releasetools/add_img_to_target_files.py
index 44719ed..6994430 100755
--- a/tools/releasetools/add_img_to_target_files.py
+++ b/tools/releasetools/add_img_to_target_files.py
@@ -126,7 +126,7 @@
   if not image_size:
     return None
 
-  image_blocks = int(image_size) / 4096 - 1
+  image_blocks = int(image_size) // 4096 - 1
   assert image_blocks > 0, "blocks for {} must be positive".format(which)
 
   # For sparse images, we will only check the blocks that are listed in the care
@@ -154,16 +154,16 @@
     return img.name
 
   def output_sink(fn, data):
-    ofile = open(os.path.join(OPTIONS.input_tmp, "SYSTEM", fn), "w")
-    ofile.write(data)
-    ofile.close()
+    output_file = os.path.join(OPTIONS.input_tmp, "SYSTEM", fn)
+    with open(output_file, "wb") as ofile:
+      ofile.write(data)
 
     if output_zip:
       arc_name = "SYSTEM/" + fn
       if arc_name in output_zip.namelist():
         OPTIONS.replace_updated_files_list.append(arc_name)
       else:
-        common.ZipWrite(output_zip, ofile.name, arc_name)
+        common.ZipWrite(output_zip, output_file, arc_name)
 
   if (OPTIONS.rebuild_recovery and recovery_img is not None and
       boot_img is not None):
@@ -290,7 +290,7 @@
 
 
 def CreateImage(input_dir, info_dict, what, output_file, block_list=None):
-  logger.info("creating " + what + ".img...")
+  logger.info("creating %s.img...", what)
 
   image_props = build_image.ImagePropFromGlobalDict(info_dict, what)
   fstab = info_dict["fstab"]
@@ -778,7 +778,7 @@
   partitions = dict()
 
   def banner(s):
-    logger.info("\n\n++++ " + s + " ++++\n\n")
+    logger.info("\n\n++++ %s  ++++\n\n", s)
 
   boot_image = None
   if has_boot:
@@ -901,7 +901,7 @@
   ab_partitions_txt = os.path.join(OPTIONS.input_tmp, "META",
                                    "ab_partitions.txt")
   if os.path.exists(ab_partitions_txt):
-    with open(ab_partitions_txt, 'r') as f:
+    with open(ab_partitions_txt) as f:
       ab_partitions = f.readlines()
 
     # For devices using A/B update, make sure we have all the needed images
@@ -916,7 +916,7 @@
   pack_radioimages_txt = os.path.join(
       OPTIONS.input_tmp, "META", "pack_radioimages.txt")
   if os.path.exists(pack_radioimages_txt):
-    with open(pack_radioimages_txt, 'r') as f:
+    with open(pack_radioimages_txt) as f:
       AddPackRadioImages(output_zip, f.readlines())
 
   if output_zip:
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index 4bebef5..f8cb7e9 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -54,7 +54,9 @@
       base_search_path = os.path.join(base_out_path,
                                       os.path.basename(os.getcwd()))
 
+    # Python >= 3.3 returns 'linux', whereas Python 2.7 gives 'linux2'.
     platform_search_path = {
+        "linux": os.path.join(base_search_path, "host/linux-x86"),
         "linux2": os.path.join(base_search_path, "host/linux-x86"),
         "darwin": os.path.join(base_search_path, "host/darwin-x86"),
     }
diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py
index 3442b27..0e84327 100755
--- a/tools/releasetools/ota_from_target_files.py
+++ b/tools/releasetools/ota_from_target_files.py
@@ -1938,7 +1938,7 @@
   target_file = common.MakeTempFile(prefix="targetfiles-", suffix=".zip")
   shutil.copyfile(input_file, target_file)
 
-  with zipfile.ZipFile(input_file, 'r') as input_zip:
+  with zipfile.ZipFile(input_file) as input_zip:
     namelist = input_zip.namelist()
 
   input_tmp = common.UnzipTemp(input_file, RETROFIT_DAP_UNZIP_PATTERN)
diff --git a/tools/releasetools/sign_target_files_apks.py b/tools/releasetools/sign_target_files_apks.py
index 668ad9b..4a7b34b 100755
--- a/tools/releasetools/sign_target_files_apks.py
+++ b/tools/releasetools/sign_target_files_apks.py
@@ -154,11 +154,11 @@
 
 def GetApkCerts(certmap):
   # apply the key remapping to the contents of the file
-  for apk, cert in certmap.iteritems():
+  for apk, cert in certmap.items():
     certmap[apk] = OPTIONS.key_map.get(cert, cert)
 
   # apply all the -e options, overriding anything in the file
-  for apk, cert in OPTIONS.extra_apks.iteritems():
+  for apk, cert in OPTIONS.extra_apks.items():
     if not cert:
       cert = "PRESIGNED"
     certmap[apk] = OPTIONS.key_map.get(cert, cert)
@@ -519,14 +519,14 @@
       if stat.S_ISLNK(info.external_attr >> 16):
         new_data = data
       else:
-        new_data = RewriteProps(data)
+        new_data = RewriteProps(data.decode())
       common.ZipWriteStr(output_tf_zip, out_info, new_data)
 
     # Replace the certs in *mac_permissions.xml (there could be multiple, such
     # as {system,vendor}/etc/selinux/{plat,nonplat}_mac_permissions.xml).
     elif filename.endswith("mac_permissions.xml"):
       print("Rewriting %s with new keys." % (filename,))
-      new_data = ReplaceCerts(data)
+      new_data = ReplaceCerts(data.decode())
       common.ZipWriteStr(output_tf_zip, out_info, new_data)
 
     # Ask add_img_to_target_files to rebuild the recovery patch if needed.
@@ -630,17 +630,17 @@
   Raises:
     AssertionError: On finding duplicate entries.
   """
-  for old, new in OPTIONS.key_map.iteritems():
+  for old, new in OPTIONS.key_map.items():
     if OPTIONS.verbose:
       print("    Replacing %s.x509.pem with %s.x509.pem" % (old, new))
 
     try:
       with open(old + ".x509.pem") as old_fp:
         old_cert16 = base64.b16encode(
-            common.ParseCertificate(old_fp.read())).lower()
+            common.ParseCertificate(old_fp.read())).decode().lower()
       with open(new + ".x509.pem") as new_fp:
         new_cert16 = base64.b16encode(
-            common.ParseCertificate(new_fp.read())).lower()
+            common.ParseCertificate(new_fp.read())).decode().lower()
     except IOError as e:
       if OPTIONS.verbose or e.errno != errno.ENOENT:
         print("    Error accessing %s: %s.\nSkip replacing %s.x509.pem with "
@@ -858,7 +858,7 @@
         writable.
     key_path: The path to the PEM encoded X.509 certificate.
   """
-  in_cmdline = input_zip.read("BOOT/cmdline")
+  in_cmdline = input_zip.read("BOOT/cmdline").decode()
   # Copy in_cmdline to output_zip if veritykeyid is not present.
   if "veritykeyid" not in in_cmdline:
     common.ZipWriteStr(output_zip, "BOOT/cmdline", in_cmdline)
@@ -891,7 +891,7 @@
   current in-memory dict contains additional items computed at runtime.
   """
   misc_info_old = common.LoadDictionaryFromLines(
-      input_zip.read('META/misc_info.txt').split('\n'))
+      input_zip.read('META/misc_info.txt').decode().split('\n'))
   items = []
   for key in sorted(misc_info):
     if key in misc_info_old:
@@ -957,7 +957,7 @@
 
 
 def GetApiLevelAndCodename(input_tf_zip):
-  data = input_tf_zip.read("SYSTEM/build.prop")
+  data = input_tf_zip.read("SYSTEM/build.prop").decode()
   api_level = None
   codename = None
   for line in data.split("\n"):
@@ -979,7 +979,7 @@
 
 
 def GetCodenameToApiLevelMap(input_tf_zip):
-  data = input_tf_zip.read("SYSTEM/build.prop")
+  data = input_tf_zip.read("SYSTEM/build.prop").decode()
   api_level = None
   codenames = None
   for line in data.split("\n"):
@@ -997,7 +997,7 @@
   if codenames is None:
     raise ValueError("No ro.build.version.all_codenames in SYSTEM/build.prop")
 
-  result = dict()
+  result = {}
   for codename in codenames:
     codename = codename.strip()
     if codename:
@@ -1021,7 +1021,7 @@
         key.
   """
   keys = {}
-  for line in tf_zip.read("META/apexkeys.txt").split("\n"):
+  for line in tf_zip.read('META/apexkeys.txt').decode().split('\n'):
     line = line.strip()
     if not line:
       continue
diff --git a/tools/releasetools/test_sign_target_files_apks.py b/tools/releasetools/test_sign_target_files_apks.py
index e142ebb..9a1d163 100644
--- a/tools/releasetools/test_sign_target_files_apks.py
+++ b/tools/releasetools/test_sign_target_files_apks.py
@@ -136,7 +136,7 @@
       ReplaceVerityKeyId(input_zip, output_zip, cert_file)
 
     with zipfile.ZipFile(output_file) as output_zip:
-      self.assertEqual(BOOT_CMDLINE1, output_zip.read('BOOT/cmdline'))
+      self.assertEqual(BOOT_CMDLINE1, output_zip.read('BOOT/cmdline').decode())
 
     # Test with the second certificate.
     cert_file = os.path.join(self.testdata_dir, 'testkey.x509.pem')
@@ -146,7 +146,7 @@
       ReplaceVerityKeyId(input_zip, output_zip, cert_file)
 
     with zipfile.ZipFile(output_file) as output_zip:
-      self.assertEqual(BOOT_CMDLINE2, output_zip.read('BOOT/cmdline'))
+      self.assertEqual(BOOT_CMDLINE2, output_zip.read('BOOT/cmdline').decode())
 
   def test_ReplaceVerityKeyId_no_veritykeyid(self):
     BOOT_CMDLINE = (
@@ -164,7 +164,7 @@
       ReplaceVerityKeyId(input_zip, output_zip, None)
 
     with zipfile.ZipFile(output_file) as output_zip:
-      self.assertEqual(BOOT_CMDLINE, output_zip.read('BOOT/cmdline'))
+      self.assertEqual(BOOT_CMDLINE, output_zip.read('BOOT/cmdline').decode())
 
   def test_ReplaceCerts(self):
     cert1_path = os.path.join(self.testdata_dir, 'platform.x509.pem')
diff --git a/tools/releasetools/test_validate_target_files.py b/tools/releasetools/test_validate_target_files.py
index 70e3b49..0f0d773 100644
--- a/tools/releasetools/test_validate_target_files.py
+++ b/tools/releasetools/test_validate_target_files.py
@@ -98,7 +98,7 @@
     with open(boot_image, 'r+b') as boot_fp:
       boot_fp.seek(-1, os.SEEK_END)
       last_byte = boot_fp.read(1)
-      last_byte = chr(255 - ord(last_byte))
+      last_byte = bytes([255 - ord(last_byte)])
       boot_fp.seek(-1, os.SEEK_END)
       boot_fp.write(last_byte)