diff --git a/tools/releasetools/build_image.py b/tools/releasetools/build_image.py
index bcbc921..d2f4e25 100755
--- a/tools/releasetools/build_image.py
+++ b/tools/releasetools/build_image.py
@@ -740,28 +740,6 @@
     f.writelines(["%s=%s" % (key, value) for (key, value) in glob_dict.items()])
 
 
-def ExtractSystemOtherAvbKey(in_dir, glob_dict):
-  if glob_dict.get("avb_system_extract_system_other_key") != "true":
-    return
-
-  extract_to = os.path.join(in_dir, "etc/security/avb/system_other.avbpubkey")
-  extract_to_dir = os.path.dirname(extract_to)
-
-  if os.path.isdir(extract_to_dir):
-    shutil.rmtree(extract_to_dir)
-  elif os.path.isfile(extract_to_dir):
-    os.remove(extract_to_dir)
-  os.mkdir(extract_to_dir);
-
-  # Extracts the public key used to sign system_other.img, into system.img:
-  #   /system/etc/security/avb/system_other.avbpubkey.
-  avbtool = glob_dict.get("avb_avbtool")
-  extract_from = glob_dict.get("avb_system_other_key_path")
-  cmd = [avbtool, "extract_public_key", "--key", extract_from,
-         "--output", extract_to]
-  common.RunAndCheckOutput(cmd, verbose=False)
-
-
 def main(argv):
   if len(argv) < 4 or len(argv) > 5:
     print(__doc__)
@@ -785,7 +763,6 @@
     mount_point = ""
     if image_filename == "system.img":
       mount_point = "system"
-      ExtractSystemOtherAvbKey(in_dir, glob_dict)
     elif image_filename == "system_other.img":
       mount_point = "system_other"
     elif image_filename == "userdata.img":
diff --git a/tools/releasetools/sign_target_files_apks.py b/tools/releasetools/sign_target_files_apks.py
index 71598e3..75a98fd 100755
--- a/tools/releasetools/sign_target_files_apks.py
+++ b/tools/releasetools/sign_target_files_apks.py
@@ -91,12 +91,12 @@
       Replace the veritykeyid in BOOT/cmdline of input_target_file_zip
       with keyid of the cert pointed by <path_to_X509_PEM_cert_file>.
 
-  --avb_{boot,system,vendor,dtbo,vbmeta}_algorithm <algorithm>
-  --avb_{boot,system,vendor,dtbo,vbmeta}_key <key>
+  --avb_{boot,system,system_other,vendor,dtbo,vbmeta}_algorithm <algorithm>
+  --avb_{boot,system,system_other,vendor,dtbo,vbmeta}_key <key>
       Use the specified algorithm (e.g. SHA256_RSA4096) and the key to AVB-sign
       the specified image. Otherwise it uses the existing values in info dict.
 
-  --avb_{apex,boot,system,vendor,dtbo,vbmeta}_extra_args <args>
+  --avb_{apex,boot,system,system_other,vendor,dtbo,vbmeta}_extra_args <args>
       Specify any additional args that are needed to AVB-sign the image
       (e.g. "--signing_helper /path/to/helper"). The args will be appended to
       the existing ones in info dict.
@@ -584,6 +584,18 @@
     elif filename == "META/care_map.pb" or filename == "META/care_map.txt":
       pass
 
+    # Updates system_other.avbpubkey in /product/etc/.
+    elif filename in (
+        "PRODUCT/etc/security/avb/system_other.avbpubkey",
+        "SYSTEM/product/etc/security/avb/system_other.avbpubkey"):
+      # Only update system_other's public key, if the corresponding signing
+      # key is specified via --avb_system_other_key.
+      signing_key = OPTIONS.avb_keys.get("system_other")
+      if signing_key:
+        public_key = common.ExtractAvbPublicKey(signing_key)
+        print("    Rewriting AVB public key of system_other in /product")
+        common.ZipWrite(output_tf_zip, public_key, filename)
+
     # A non-APK file; copy it verbatim.
     else:
       common.ZipWriteStr(output_tf_zip, out_info, data)
@@ -934,6 +946,7 @@
       'dtbo' : 'avb_dtbo_add_hash_footer_args',
       'recovery' : 'avb_recovery_add_hash_footer_args',
       'system' : 'avb_system_add_hashtree_footer_args',
+      'system_other' : 'avb_system_other_add_hashtree_footer_args',
       'vendor' : 'avb_vendor_add_hashtree_footer_args',
       'vbmeta' : 'avb_vbmeta_args',
   }
@@ -1153,6 +1166,12 @@
       OPTIONS.avb_algorithms['system'] = a
     elif o == "--avb_system_extra_args":
       OPTIONS.avb_extra_args['system'] = a
+    elif o == "--avb_system_other_key":
+      OPTIONS.avb_keys['system_other'] = a
+    elif o == "--avb_system_other_algorithm":
+      OPTIONS.avb_algorithms['system_other'] = a
+    elif o == "--avb_system_other_extra_args":
+      OPTIONS.avb_extra_args['system_other'] = a
     elif o == "--avb_vendor_key":
       OPTIONS.avb_keys['vendor'] = a
     elif o == "--avb_vendor_algorithm":
@@ -1192,6 +1211,9 @@
           "avb_system_algorithm=",
           "avb_system_key=",
           "avb_system_extra_args=",
+          "avb_system_other_algorithm=",
+          "avb_system_other_key=",
+          "avb_system_other_extra_args=",
           "avb_vendor_algorithm=",
           "avb_vendor_key=",
           "avb_vendor_extra_args=",