diff --git a/README.md b/README.md
index 136e2f7..ad1e79f 100644
--- a/README.md
+++ b/README.md
@@ -769,6 +769,15 @@
 uppercase partition name, in this case for the partition named 'foo'.
 The token will be replaced by the digest in hexadecimal form.
 
+By default, when the `--use_persistent_digest` option is used with
+`add_hash_footer` or `add_hashtree_footer`, avbtool will generate a
+descriptor with no salt rather than the typical default of generating a
+random salt equal to the digest length. This is because the digest
+value is stored in persistent storage and thus cannot change over time.
+An alternative option would be to manually provide a random salt using
+`--salt`, but this salt would need to remain unchanged for the life
+of the device once the persistent digest value was written.
+
 ## Updating Stored Rollback Indexes
 
 In order for Rollback Protection to work the bootloader will need to
diff --git a/avbtool b/avbtool
index 6f327f6..b027bbd 100755
--- a/avbtool
+++ b/avbtool
@@ -3036,9 +3036,10 @@
       if salt:
         salt = salt.decode('hex')
       else:
-        if salt is None:
-          # If salt is not explicitly specified, choose a hash
-          # that's the same size as the hash size.
+        if salt is None and not use_persistent_digest:
+          # If salt is not explicitly specified, choose a hash that's the same
+          # size as the hash size. Don't populate a random salt if this
+          # descriptor is being created to use a persistent digest on device.
           hash_size = digest_size
           salt = open('/dev/urandom').read(hash_size)
         else:
@@ -3265,9 +3266,10 @@
       if salt:
         salt = salt.decode('hex')
       else:
-        if salt is None:
-          # If salt is not explicitly specified, choose a hash
-          # that's the same size as the hash size.
+        if salt is None and not use_persistent_root_digest:
+          # If salt is not explicitly specified, choose a hash that's the same
+          # size as the hash size. Don't populate a random salt if this
+          # descriptor is being created to use a persistent digest on device.
           hash_size = digest_size
           salt = open('/dev/urandom').read(hash_size)
         else:
diff --git a/test/avb_slot_verify_unittest.cc b/test/avb_slot_verify_unittest.cc
index f8da839..f63e831 100644
--- a/test/avb_slot_verify_unittest.cc
+++ b/test/avb_slot_verify_unittest.cc
@@ -2680,7 +2680,6 @@
                    " --rollback_index 0"
                    " --partition_name factory"
                    " --partition_size %zd"
-                   " --salt deadbeef"
                    " --internal_release_string \"\""
                    " --use_persistent_digest %s",
                    factory_path.value().c_str(),
@@ -2709,7 +2708,7 @@
                                  "      Image Size:            5242880 bytes\n"
                                  "      Hash Algorithm:        sha256\n"
                                  "      Partition Name:        factory\n"
-                                 "      Salt:                  deadbeef\n"
+                                 "      Salt:                  \n"
                                  "      Digest:                \n"
                                  "      Flags:                 %d\n",
                                  do_not_use_ab ? 1 : 0),
@@ -2732,7 +2731,6 @@
         " --rollback_index 0"
         " --partition_name factory"
         " --partition_size %zd"
-        " --salt deadbeef"
         " --hash_algorithm %s"
         " --internal_release_string \"\""
         " --kernel_cmdline "
@@ -2782,7 +2780,7 @@
                                  "      FEC size:              49152 bytes\n"
                                  "      Hash Algorithm:        %s\n"
                                  "      Partition Name:        factory\n"
-                                 "      Salt:                  deadbeef\n"
+                                 "      Salt:                  \n"
                                  "      Root Digest:           \n"
                                  "      Flags:                 %d\n",
                                  expected_tree_size,
diff --git a/test/avbtool_unittest.cc b/test/avbtool_unittest.cc
index 45b1083..c436a2a 100644
--- a/test/avbtool_unittest.cc
+++ b/test/avbtool_unittest.cc
@@ -760,7 +760,7 @@
   size_t partition_size = 1024 * 1024;
   base::FilePath path = GenerateImage("digest_location", 1024);
   EXPECT_COMMAND(0,
-                 "./avbtool add_hash_footer --salt d00df00d "
+                 "./avbtool add_hash_footer "
                  "--hash_algorithm sha256 --image %s "
                  "--partition_size %d --partition_name foobar "
                  "--algorithm SHA256_RSA2048 "
@@ -792,7 +792,7 @@
       "      Image Size:            1024 bytes\n"
       "      Hash Algorithm:        sha256\n"
       "      Partition Name:        foobar\n"
-      "      Salt:                  d00df00d\n"
+      "      Salt:                  \n"
       "      Digest:                \n"
       "      Flags:                 0\n",
       InfoImage(path));
@@ -845,7 +845,7 @@
   size_t partition_size = 1024 * 1024;
   base::FilePath path = GenerateImage("digest_location", 1024);
   EXPECT_COMMAND(0,
-                 "./avbtool add_hash_footer --salt d00df00d "
+                 "./avbtool add_hash_footer "
                  "--hash_algorithm sha256 --image %s "
                  "--partition_size %d --partition_name foobar "
                  "--algorithm SHA256_RSA2048 "
@@ -878,7 +878,7 @@
       "      Image Size:            1024 bytes\n"
       "      Hash Algorithm:        sha256\n"
       "      Partition Name:        foobar\n"
-      "      Salt:                  d00df00d\n"
+      "      Salt:                  \n"
       "      Digest:                \n"
       "      Flags:                 1\n",
       InfoImage(path));
@@ -1455,7 +1455,7 @@
   size_t partition_size = 10 * 1024 * 1024;
   base::FilePath path = GenerateImage("digest_location", partition_size / 2);
   EXPECT_COMMAND(0,
-                 "./avbtool add_hashtree_footer --salt d00df00d "
+                 "./avbtool add_hashtree_footer "
                  "--hash_algorithm sha256 --image %s "
                  "--partition_size %d --partition_name foobar "
                  "--algorithm SHA256_RSA2048 "
@@ -1495,7 +1495,7 @@
       "      FEC size:              49152 bytes\n"
       "      Hash Algorithm:        sha256\n"
       "      Partition Name:        foobar\n"
-      "      Salt:                  d00df00d\n"
+      "      Salt:                  \n"
       "      Root Digest:           \n"
       "      Flags:                 0\n",
       InfoImage(path));
@@ -1556,7 +1556,7 @@
   size_t partition_size = 10 * 1024 * 1024;
   base::FilePath path = GenerateImage("digest_location", partition_size / 2);
   EXPECT_COMMAND(0,
-                 "./avbtool add_hashtree_footer --salt d00df00d "
+                 "./avbtool add_hashtree_footer "
                  "--hash_algorithm sha256 --image %s "
                  "--partition_size %d --partition_name foobar "
                  "--algorithm SHA256_RSA2048 "
@@ -1597,7 +1597,7 @@
       "      FEC size:              49152 bytes\n"
       "      Hash Algorithm:        sha256\n"
       "      Partition Name:        foobar\n"
-      "      Salt:                  d00df00d\n"
+      "      Salt:                  \n"
       "      Root Digest:           \n"
       "      Flags:                 1\n",
       InfoImage(path));