diff --git a/gki/certify_bootimg.py b/gki/certify_bootimg.py
index 5b642c5..57b124a 100755
--- a/gki/certify_bootimg.py
+++ b/gki/certify_bootimg.py
@@ -151,6 +151,20 @@
     subprocess.check_call(avbtool_cmd)
 
 
+def load_dict_from_file(path):
+    """Loads key=value pairs from |path| and returns a dict."""
+    d = {}
+    with open(path, 'r', encoding='utf-8') as f:
+        for line in f:
+            line = line.strip()
+            if not line or line.startswith('#'):
+                continue
+            if '=' in line:
+                name, value = line.split('=', 1)
+                d[name] = value
+    return d
+
+
 def parse_cmdline():
     """Parse command-line options."""
     parser = ArgumentParser(add_help=True)
@@ -203,10 +217,15 @@
     """Similar to certify_bootimg(), but for a zip archive of boot images."""
     with tempfile.TemporaryDirectory() as unzip_dir:
         shutil.unpack_archive(boot_img_zip, unzip_dir)
+
+        info_dict = load_dict_from_file(os.path.join(unzip_dir, 'gki-info.txt'))
+        extra_args.extend(info_dict['certify_bootimg_extra_args'].split())
+
         for boot_img in glob.glob(os.path.join(unzip_dir, 'boot-*.img')):
             print(f'Certifying {os.path.basename(boot_img)} ...')
             certify_bootimg(boot_img=boot_img, output_img=boot_img,
                             algorithm=algorithm, key=key, extra_args=extra_args)
+
         print(f'Making certified archive: {output_zip}')
         archive_base_name = os.path.splitext(output_zip)[0]
         shutil.make_archive(archive_base_name, 'zip', unzip_dir)
diff --git a/gki/certify_bootimg_test.py b/gki/certify_bootimg_test.py
index c84b58b..4c1ef1e 100644
--- a/gki/certify_bootimg_test.py
+++ b/gki/certify_bootimg_test.py
@@ -71,6 +71,9 @@
 def generate_test_boot_image_archive(output_zip, boot_img_info):
     """Generates a zip archive of test boot images.
 
+    It also adds a file gki-info.txt, which contains additional settings for
+    for `certify_bootimg --extra_args`.
+
     Args:
         output_zip: the output zip archive, e.g., /path/to/boot-img.zip.
         boot_img_info: a list of (boot_image_name, kernel_size,
@@ -86,6 +89,14 @@
                                      seed=name,
                                      avb_partition_size=partition_size)
 
+        gki_info = os.path.join(temp_out_dir, 'gki-info.txt')
+        with open(gki_info, 'w', encoding='utf-8') as f:
+            f.write('certify_bootimg_extra_args='
+                    '--prop KERNEL_RELEASE:5.10.42'
+                    '-android13-0-00544-ged21d463f856 '
+                    '--prop BRANCH:android13-5.10-2022-05 '
+                    '--prop BUILD_NUMBER:ab8295296\n')
+
         archive_base_name = os.path.splitext(output_zip)[0]
         shutil.make_archive(archive_base_name, 'zip', temp_out_dir)
 
@@ -309,7 +320,7 @@
             'Minimum libavb version:   1.0\n'
             'Header Block:             256 bytes\n'
             'Authentication Block:     576 bytes\n'
-            'Auxiliary Block:          1344 bytes\n'
+            'Auxiliary Block:          1536 bytes\n'
             'Public key (sha1):        '
             '2597c218aae470a130f61162feaae70afd97f011\n'
             'Algorithm:                SHA256_RSA4096\n'    # RSA4096
@@ -329,13 +340,17 @@
             '      Flags:                 0\n'
             "    Prop: foo -> 'bar'\n"
             "    Prop: gki -> 'nice'\n"
+            "    Prop: KERNEL_RELEASE -> '5.10.42-android13-0-00544-"
+            "ged21d463f856'\n"
+            "    Prop: BRANCH -> 'android13-5.10-2022-05'\n"
+            "    Prop: BUILD_NUMBER -> 'ab8295296'\n"
         )
 
         self._EXPECTED_BOOT_1_0_SIGNATURE2_RSA4096 = (   # pylint: disable=C0103
             'Minimum libavb version:   1.0\n'
             'Header Block:             256 bytes\n'
             'Authentication Block:     576 bytes\n'
-            'Auxiliary Block:          1344 bytes\n'
+            'Auxiliary Block:          1536 bytes\n'
             'Public key (sha1):        '
             '2597c218aae470a130f61162feaae70afd97f011\n'
             'Algorithm:                SHA256_RSA4096\n'    # RSA4096
@@ -355,13 +370,17 @@
             '      Flags:                 0\n'
             "    Prop: foo -> 'bar'\n"
             "    Prop: gki -> 'nice'\n"
+            "    Prop: KERNEL_RELEASE -> '5.10.42-android13-0-00544-"
+            "ged21d463f856'\n"
+            "    Prop: BRANCH -> 'android13-5.10-2022-05'\n"
+            "    Prop: BUILD_NUMBER -> 'ab8295296'\n"
         )
 
         self._EXPECTED_BOOT_2_0_SIGNATURE1_RSA4096 = (   # pylint: disable=C0103
             'Minimum libavb version:   1.0\n'
             'Header Block:             256 bytes\n'
             'Authentication Block:     576 bytes\n'
-            'Auxiliary Block:          1344 bytes\n'
+            'Auxiliary Block:          1536 bytes\n'
             'Public key (sha1):        '
             '2597c218aae470a130f61162feaae70afd97f011\n'
             'Algorithm:                SHA256_RSA4096\n'    # RSA4096
@@ -381,13 +400,17 @@
             '      Flags:                 0\n'
             "    Prop: foo -> 'bar'\n"
             "    Prop: gki -> 'nice'\n"
+            "    Prop: KERNEL_RELEASE -> '5.10.42-android13-0-00544-"
+            "ged21d463f856'\n"
+            "    Prop: BRANCH -> 'android13-5.10-2022-05'\n"
+            "    Prop: BUILD_NUMBER -> 'ab8295296'\n"
         )
 
         self._EXPECTED_BOOT_2_0_SIGNATURE2_RSA4096 = (   # pylint: disable=C0103
             'Minimum libavb version:   1.0\n'
             'Header Block:             256 bytes\n'
             'Authentication Block:     576 bytes\n'
-            'Auxiliary Block:          1344 bytes\n'
+            'Auxiliary Block:          1536 bytes\n'
             'Public key (sha1):        '
             '2597c218aae470a130f61162feaae70afd97f011\n'
             'Algorithm:                SHA256_RSA4096\n'    # RSA4096
@@ -407,6 +430,10 @@
             '      Flags:                 0\n'
             "    Prop: foo -> 'bar'\n"
             "    Prop: gki -> 'nice'\n"
+            "    Prop: KERNEL_RELEASE -> '5.10.42-android13-0-00544-"
+            "ged21d463f856'\n"
+            "    Prop: BRANCH -> 'android13-5.10-2022-05'\n"
+            "    Prop: BUILD_NUMBER -> 'ab8295296'\n"
         )
 
     def _test_boot_signatures(self, signatures_dir, expected_signatures_info):