diff --git a/payload_consumer/delta_performer.cc b/payload_consumer/delta_performer.cc
index cc39943..ee5f38c 100644
--- a/payload_consumer/delta_performer.cc
+++ b/payload_consumer/delta_performer.cc
@@ -713,8 +713,7 @@
 
   // In major version 2, we don't add dummy operation to the payload.
   // If we already extracted the signature we should skip this step.
-  if (major_payload_version_ == kBrilloMajorPayloadVersion &&
-      manifest_.has_signatures_offset() && manifest_.has_signatures_size() &&
+  if (manifest_.has_signatures_offset() && manifest_.has_signatures_size() &&
       signatures_message_data_.empty()) {
     if (manifest_.signatures_offset() != buffer_offset_) {
       LOG(ERROR) << "Payload signatures offset points to blob offset "
@@ -749,51 +748,11 @@
 }
 
 bool DeltaPerformer::ParseManifestPartitions(ErrorCode* error) {
-  if (major_payload_version_ == kBrilloMajorPayloadVersion) {
-    partitions_.clear();
-    for (const PartitionUpdate& partition : manifest_.partitions()) {
-      partitions_.push_back(partition);
-    }
-    manifest_.clear_partitions();
-  } else if (major_payload_version_ == kChromeOSMajorPayloadVersion) {
-    LOG(INFO) << "Converting update information from old format.";
-    PartitionUpdate root_part;
-    root_part.set_partition_name(kPartitionNameRoot);
-#ifdef __ANDROID__
-    LOG(WARNING) << "Legacy payload major version provided to an Android "
-                    "build. Assuming no post-install. Please use major version "
-                    "2 or newer.";
-    root_part.set_run_postinstall(false);
-#else
-    root_part.set_run_postinstall(true);
-#endif  // __ANDROID__
-    if (manifest_.has_old_rootfs_info()) {
-      *root_part.mutable_old_partition_info() = manifest_.old_rootfs_info();
-      manifest_.clear_old_rootfs_info();
-    }
-    if (manifest_.has_new_rootfs_info()) {
-      *root_part.mutable_new_partition_info() = manifest_.new_rootfs_info();
-      manifest_.clear_new_rootfs_info();
-    }
-    *root_part.mutable_operations() = manifest_.install_operations();
-    manifest_.clear_install_operations();
-    partitions_.push_back(std::move(root_part));
-
-    PartitionUpdate kern_part;
-    kern_part.set_partition_name(kPartitionNameKernel);
-    kern_part.set_run_postinstall(false);
-    if (manifest_.has_old_kernel_info()) {
-      *kern_part.mutable_old_partition_info() = manifest_.old_kernel_info();
-      manifest_.clear_old_kernel_info();
-    }
-    if (manifest_.has_new_kernel_info()) {
-      *kern_part.mutable_new_partition_info() = manifest_.new_kernel_info();
-      manifest_.clear_new_kernel_info();
-    }
-    *kern_part.mutable_operations() = manifest_.kernel_install_operations();
-    manifest_.clear_kernel_install_operations();
-    partitions_.push_back(std::move(kern_part));
+  partitions_.clear();
+  for (const PartitionUpdate& partition : manifest_.partitions()) {
+    partitions_.push_back(partition);
   }
+  manifest_.clear_partitions();
 
   // Fill in the InstallPlan::partitions based on the partitions from the
   // payload.
@@ -954,14 +913,6 @@
   TEST_AND_RETURN_FALSE(buffer_offset_ == operation.data_offset());
   TEST_AND_RETURN_FALSE(buffer_.size() >= operation.data_length());
 
-  // Extract the signature message if it's in this operation.
-  if (ExtractSignatureMessageFromOperation(operation)) {
-    // If this is dummy replace operation, we ignore it after extracting the
-    // signature.
-    DiscardBuffer(true, 0);
-    return true;
-  }
-
   // Setup the ExtentWriter stack based on the operation type.
   std::unique_ptr<ExtentWriter> writer = std::make_unique<DirectExtentWriter>();
 
@@ -1412,19 +1363,6 @@
   return true;
 }
 
-bool DeltaPerformer::ExtractSignatureMessageFromOperation(
-    const InstallOperation& operation) {
-  if (operation.type() != InstallOperation::REPLACE ||
-      !manifest_.has_signatures_offset() ||
-      manifest_.signatures_offset() != operation.data_offset()) {
-    return false;
-  }
-  TEST_AND_RETURN_FALSE(manifest_.has_signatures_size() &&
-                        manifest_.signatures_size() == operation.data_length());
-  TEST_AND_RETURN_FALSE(ExtractSignatureMessage());
-  return true;
-}
-
 bool DeltaPerformer::ExtractSignatureMessage() {
   TEST_AND_RETURN_FALSE(signatures_message_data_.empty());
   TEST_AND_RETURN_FALSE(buffer_offset_ == manifest_.signatures_offset());
@@ -1476,11 +1414,11 @@
   // Perform assorted checks to sanity check the manifest, make sure it
   // matches data from other sources, and that it is a supported version.
 
-  bool has_old_fields =
-      (manifest_.has_old_kernel_info() || manifest_.has_old_rootfs_info());
-  for (const PartitionUpdate& partition : manifest_.partitions()) {
-    has_old_fields = has_old_fields || partition.has_old_partition_info();
-  }
+  bool has_old_fields = std::any_of(manifest_.partitions().begin(),
+                                    manifest_.partitions().end(),
+                                    [](const PartitionUpdate& partition) {
+                                      return partition.has_old_partition_info();
+                                    });
 
   // The presence of an old partition hash is the sole indicator for a delta
   // update.
@@ -1522,16 +1460,12 @@
     }
   }
 
-  if (major_payload_version_ != kChromeOSMajorPayloadVersion) {
-    if (manifest_.has_old_rootfs_info() || manifest_.has_new_rootfs_info() ||
-        manifest_.has_old_kernel_info() || manifest_.has_new_kernel_info() ||
-        manifest_.install_operations_size() != 0 ||
-        manifest_.kernel_install_operations_size() != 0) {
-      LOG(ERROR) << "Manifest contains deprecated field only supported in "
-                 << "major payload version 1, but the payload major version is "
-                 << major_payload_version_;
-      return ErrorCode::kPayloadMismatchedType;
-    }
+  if (manifest_.has_old_rootfs_info() || manifest_.has_new_rootfs_info() ||
+      manifest_.has_old_kernel_info() || manifest_.has_new_kernel_info() ||
+      manifest_.install_operations_size() != 0 ||
+      manifest_.kernel_install_operations_size() != 0) {
+    LOG(ERROR) << "Manifest contains deprecated fields.";
+    return ErrorCode::kPayloadMismatchedType;
   }
 
   if (manifest_.max_timestamp() < hardware_->GetBuildTimestamp()) {
@@ -1542,18 +1476,8 @@
     return ErrorCode::kPayloadTimestampError;
   }
 
-  if (major_payload_version_ == kChromeOSMajorPayloadVersion) {
-    if (manifest_.has_dynamic_partition_metadata()) {
-      LOG(ERROR)
-          << "Should not contain dynamic_partition_metadata for major version "
-          << kChromeOSMajorPayloadVersion
-          << ". Please use major version 2 or above.";
-      return ErrorCode::kPayloadMismatchedType;
-    }
-  }
-
-  // TODO(garnold) we should be adding more and more manifest checks, such as
-  // partition boundaries etc (see chromium-os:37661).
+  // TODO(crbug.com/37661) we should be adding more and more manifest checks,
+  // such as partition boundaries, etc.
 
   return ErrorCode::kSuccess;
 }
diff --git a/payload_consumer/delta_performer.h b/payload_consumer/delta_performer.h
index 4493c2a..7860747 100644
--- a/payload_consumer/delta_performer.h
+++ b/payload_consumer/delta_performer.h
@@ -237,11 +237,6 @@
   FileDescriptorPtr ChooseSourceFD(const InstallOperation& operation,
                                    ErrorCode* error);
 
-  // Extracts the payload signature message from the blob on the |operation| if
-  // the offset matches the one specified by the manifest. Returns whether the
-  // signature was extracted.
-  bool ExtractSignatureMessageFromOperation(const InstallOperation& operation);
-
   // Extracts the payload signature message from the current |buffer_| if the
   // offset matches the one specified by the manifest. Returns whether the
   // signature was extracted.
diff --git a/payload_consumer/delta_performer_integration_test.cc b/payload_consumer/delta_performer_integration_test.cc
index 904ea5a..5f55739 100644
--- a/payload_consumer/delta_performer_integration_test.cc
+++ b/payload_consumer/delta_performer_integration_test.cc
@@ -76,6 +76,7 @@
 
   string delta_path;
   uint64_t metadata_size;
+  uint32_t metadata_signature_size;
 
   string old_kernel;
   brillo::Blob old_kernel_data;
@@ -187,17 +188,32 @@
                                  uint64_t* out_metadata_size) {
   string private_key_path = GetBuildArtifactsPath(kUnittestPrivateKeyPath);
   int signature_size = GetSignatureSize(private_key_path);
-  brillo::Blob hash;
+  brillo::Blob metadata_hash, payload_hash;
   ASSERT_TRUE(PayloadSigner::HashPayloadForSigning(
-      payload_path, {signature_size}, &hash, nullptr));
-  brillo::Blob signature;
-  ASSERT_TRUE(PayloadSigner::SignHash(hash, private_key_path, &signature));
-  ASSERT_TRUE(PayloadSigner::AddSignatureToPayload(
-      payload_path, {signature}, {}, payload_path, out_metadata_size));
+      payload_path, {signature_size}, &payload_hash, &metadata_hash));
+  brillo::Blob metadata_signature, payload_signature;
+  ASSERT_TRUE(PayloadSigner::SignHash(
+      payload_hash, private_key_path, &payload_signature));
+  ASSERT_TRUE(PayloadSigner::SignHash(
+      metadata_hash, private_key_path, &metadata_signature));
+  ASSERT_TRUE(PayloadSigner::AddSignatureToPayload(payload_path,
+                                                   {payload_signature},
+                                                   {metadata_signature},
+                                                   payload_path,
+                                                   out_metadata_size));
   EXPECT_TRUE(PayloadSigner::VerifySignedPayload(
       payload_path, GetBuildArtifactsPath(kUnittestPublicKeyPath)));
 }
 
+static void SignHashToFile(const string& hash_file,
+                           const string& signature_file,
+                           const string& private_key_file) {
+  brillo::Blob hash, signature;
+  ASSERT_TRUE(utils::ReadFile(hash_file, &hash));
+  ASSERT_TRUE(PayloadSigner::SignHash(hash, private_key_file, &signature));
+  ASSERT_TRUE(test_utils::WriteFileVector(signature_file, signature));
+}
+
 static void SignGeneratedShellPayload(SignatureTest signature_test,
                                       const string& payload_path) {
   string private_key_path = GetBuildArtifactsPath(kUnittestPrivateKeyPath);
@@ -230,7 +246,8 @@
     RSA_free(rsa);
   }
   int signature_size = GetSignatureSize(private_key_path);
-  test_utils::ScopedTempFile hash_file("hash.XXXXXX");
+  test_utils::ScopedTempFile payload_hash_file("hash.XXXXXX"),
+      metadata_hash_file("hash.XXXXXX");
   string signature_size_string;
   if (signature_test == kSignatureGeneratedShellRotateCl1 ||
       signature_test == kSignatureGeneratedShellRotateCl2)
@@ -241,38 +258,51 @@
   string delta_generator_path = GetBuildArtifactsPath("delta_generator");
   ASSERT_EQ(0,
             System(base::StringPrintf(
-                "%s -in_file=%s -signature_size=%s -out_hash_file=%s",
+                "%s -in_file=%s -signature_size=%s -out_hash_file=%s "
+                "-out_metadata_hash_file=%s",
                 delta_generator_path.c_str(),
                 payload_path.c_str(),
                 signature_size_string.c_str(),
-                hash_file.path().c_str())));
+                payload_hash_file.path().c_str(),
+                metadata_hash_file.path().c_str())));
 
-  // Sign the hash
-  brillo::Blob hash, signature;
-  ASSERT_TRUE(utils::ReadFile(hash_file.path(), &hash));
-  ASSERT_TRUE(PayloadSigner::SignHash(hash, private_key_path, &signature));
+  // Sign the payload hash.
+  test_utils::ScopedTempFile payload_signature_file("signature.XXXXXX");
+  SignHashToFile(payload_hash_file.path(),
+                 payload_signature_file.path(),
+                 private_key_path);
+  string payload_sig_files = payload_signature_file.path();
+  // Sign the metadata hash.
+  test_utils::ScopedTempFile metadata_signature_file("signature.XXXXXX");
+  SignHashToFile(metadata_hash_file.path(),
+                 metadata_signature_file.path(),
+                 private_key_path);
+  string metadata_sig_files = metadata_signature_file.path();
 
-  test_utils::ScopedTempFile sig_file("signature.XXXXXX");
-  ASSERT_TRUE(test_utils::WriteFileVector(sig_file.path(), signature));
-  string sig_files = sig_file.path();
-
-  test_utils::ScopedTempFile sig_file2("signature.XXXXXX");
+  test_utils::ScopedTempFile payload_signature_file2("signature.XXXXXX");
+  test_utils::ScopedTempFile metadata_signature_file2("signature.XXXXXX");
   if (signature_test == kSignatureGeneratedShellRotateCl1 ||
       signature_test == kSignatureGeneratedShellRotateCl2) {
-    ASSERT_TRUE(PayloadSigner::SignHash(
-        hash, GetBuildArtifactsPath(kUnittestPrivateKey2Path), &signature));
-    ASSERT_TRUE(test_utils::WriteFileVector(sig_file2.path(), signature));
+    SignHashToFile(payload_hash_file.path(),
+                   payload_signature_file2.path(),
+                   GetBuildArtifactsPath(kUnittestPrivateKey2Path));
+    SignHashToFile(metadata_hash_file.path(),
+                   metadata_signature_file2.path(),
+                   GetBuildArtifactsPath(kUnittestPrivateKey2Path));
     // Append second sig file to first path
-    sig_files += ":" + sig_file2.path();
+    payload_sig_files += ":" + payload_signature_file2.path();
+    metadata_sig_files += ":" + metadata_signature_file2.path();
   }
 
-  ASSERT_EQ(0,
-            System(base::StringPrintf(
-                "%s -in_file=%s -payload_signature_file=%s -out_file=%s",
-                delta_generator_path.c_str(),
-                payload_path.c_str(),
-                sig_files.c_str(),
-                payload_path.c_str())));
+  ASSERT_EQ(
+      0,
+      System(base::StringPrintf("%s -in_file=%s -payload_signature_file=%s "
+                                "-metadata_signature_file=%s -out_file=%s",
+                                delta_generator_path.c_str(),
+                                payload_path.c_str(),
+                                payload_sig_files.c_str(),
+                                metadata_sig_files.c_str(),
+                                payload_path.c_str())));
   int verify_result = System(base::StringPrintf(
       "%s -in_file=%s -public_key=%s -public_key_version=%d",
       delta_generator_path.c_str(),
@@ -474,7 +504,7 @@
     payload_config.is_delta = !full_rootfs;
     payload_config.hard_chunk_size = chunk_size;
     payload_config.rootfs_partition_size = kRootFSPartitionSize;
-    payload_config.version.major = kChromeOSMajorPayloadVersion;
+    payload_config.version.major = kBrilloMajorPayloadVersion;
     payload_config.version.minor = minor_version;
     if (!full_rootfs) {
       payload_config.source.partitions.emplace_back(kPartitionNameRoot);
@@ -564,6 +594,9 @@
     EXPECT_TRUE(payload_metadata.ParsePayloadHeader(state->delta));
     state->metadata_size = payload_metadata.GetMetadataSize();
     LOG(INFO) << "Metadata size: " << state->metadata_size;
+    state->metadata_signature_size =
+        payload_metadata.GetMetadataSignatureSize();
+    LOG(INFO) << "Metadata signature size: " << state->metadata_signature_size;
 
     DeltaArchiveManifest manifest;
     EXPECT_TRUE(payload_metadata.GetManifest(state->delta, &manifest));
@@ -575,7 +608,8 @@
       EXPECT_TRUE(manifest.has_signatures_size());
       Signatures sigs_message;
       EXPECT_TRUE(sigs_message.ParseFromArray(
-          &state->delta[state->metadata_size + manifest.signatures_offset()],
+          &state->delta[state->metadata_size + state->metadata_signature_size +
+                        manifest.signatures_offset()],
           manifest.signatures_size()));
       if (signature_test == kSignatureGeneratedShellRotateCl1 ||
           signature_test == kSignatureGeneratedShellRotateCl2)
@@ -597,13 +631,38 @@
       EXPECT_FALSE(signature.data().empty());
     }
 
+    // TODO(ahassani): Make |DeltaState| into a partition list kind of struct
+    // instead of hardcoded kernel/rootfs so its cleaner and we can make the
+    // following code into a helper function instead.
+    const auto& kernel_part = *std::find_if(
+        manifest.partitions().begin(),
+        manifest.partitions().end(),
+        [](const PartitionUpdate& partition) {
+          return partition.partition_name() == kPartitionNameKernel;
+        });
     if (full_kernel) {
-      EXPECT_FALSE(manifest.has_old_kernel_info());
+      EXPECT_FALSE(kernel_part.has_old_partition_info());
     } else {
       EXPECT_EQ(state->old_kernel_data.size(),
-                manifest.old_kernel_info().size());
-      EXPECT_FALSE(manifest.old_kernel_info().hash().empty());
+                kernel_part.old_partition_info().size());
+      EXPECT_FALSE(kernel_part.old_partition_info().hash().empty());
     }
+    EXPECT_EQ(state->new_kernel_data.size(),
+              kernel_part.new_partition_info().size());
+    EXPECT_FALSE(kernel_part.new_partition_info().hash().empty());
+
+    const auto& rootfs_part =
+        *std::find_if(manifest.partitions().begin(),
+                      manifest.partitions().end(),
+                      [](const PartitionUpdate& partition) {
+                        return partition.partition_name() == kPartitionNameRoot;
+                      });
+    if (full_rootfs) {
+      EXPECT_FALSE(rootfs_part.has_old_partition_info());
+    } else {
+      EXPECT_FALSE(rootfs_part.old_partition_info().hash().empty());
+    }
+    EXPECT_FALSE(rootfs_part.new_partition_info().hash().empty());
 
     EXPECT_EQ(manifest.new_image_info().channel(), "test-channel");
     EXPECT_EQ(manifest.new_image_info().board(), "test-board");
@@ -620,27 +679,14 @@
       EXPECT_EQ(manifest.old_image_info().build_channel(), "src-build-channel");
       EXPECT_EQ(manifest.old_image_info().build_version(), "src-build-version");
     }
-
-    if (full_rootfs) {
-      EXPECT_FALSE(manifest.has_old_rootfs_info());
-      EXPECT_FALSE(manifest.has_old_image_info());
-      EXPECT_TRUE(manifest.has_new_image_info());
-    } else {
-      EXPECT_EQ(state->image_size, manifest.old_rootfs_info().size());
-      EXPECT_FALSE(manifest.old_rootfs_info().hash().empty());
-    }
-
-    EXPECT_EQ(state->new_kernel_data.size(), manifest.new_kernel_info().size());
-    EXPECT_EQ(state->image_size, manifest.new_rootfs_info().size());
-
-    EXPECT_FALSE(manifest.new_kernel_info().hash().empty());
-    EXPECT_FALSE(manifest.new_rootfs_info().hash().empty());
   }
 
   MockPrefs prefs;
   EXPECT_CALL(prefs, SetInt64(kPrefsManifestMetadataSize, state->metadata_size))
       .WillOnce(Return(true));
-  EXPECT_CALL(prefs, SetInt64(kPrefsManifestSignatureSize, 0))
+  EXPECT_CALL(
+      prefs,
+      SetInt64(kPrefsManifestSignatureSize, state->metadata_signature_size))
       .WillOnce(Return(true));
   EXPECT_CALL(prefs, SetInt64(kPrefsUpdateStateNextOperation, _))
       .WillRepeatedly(Return(true));
diff --git a/payload_consumer/delta_performer_unittest.cc b/payload_consumer/delta_performer_unittest.cc
index 61b58ed..0671eca 100644
--- a/payload_consumer/delta_performer_unittest.cc
+++ b/payload_consumer/delta_performer_unittest.cc
@@ -304,14 +304,16 @@
 
     // Set a valid magic string and version number 1.
     EXPECT_TRUE(performer_.Write("CrAU", 4));
-    uint64_t version = htobe64(kChromeOSMajorPayloadVersion);
+    uint64_t version = htobe64(kBrilloMajorPayloadVersion);
     EXPECT_TRUE(performer_.Write(&version, 8));
 
     payload_.metadata_size = expected_metadata_size;
     ErrorCode error_code;
-    // When filling in size in manifest, exclude the size of the 20-byte header.
-    uint64_t size_in_manifest = htobe64(actual_metadata_size - 20);
-    bool result = performer_.Write(&size_in_manifest, 8, &error_code);
+    // When filling in size in manifest, exclude the size of the 24-byte header.
+    uint64_t size_in_manifest = htobe64(actual_metadata_size - 24);
+    performer_.Write(&size_in_manifest, 8, &error_code);
+    uint32_t signature_size = htobe64(10);
+    bool result = performer_.Write(&signature_size, 4, &error_code);
     if (expected_metadata_size == actual_metadata_size ||
         !hash_checks_mandatory) {
       EXPECT_TRUE(result);
@@ -333,7 +335,7 @@
     brillo::Blob payload = GeneratePayload(brillo::Blob(),
                                            vector<AnnotatedOperation>(),
                                            sign_payload,
-                                           kChromeOSMajorPayloadVersion,
+                                           kBrilloMajorPayloadVersion,
                                            kFullPayloadMinorVersion);
 
     LOG(INFO) << "Payload size: " << payload.size();
@@ -347,6 +349,9 @@
     switch (metadata_signature_test) {
       case kEmptyMetadataSignature:
         payload_.metadata_signature.clear();
+        // We need to set the signature size in a signed payload to zero.
+        std::fill(
+            std::next(payload.begin(), 20), std::next(payload.begin(), 24), 0);
         expected_result = MetadataParseResult::kError;
         expected_error = ErrorCode::kDownloadMetadataSignatureMissingError;
         break;
@@ -447,7 +452,7 @@
   brillo::Blob payload_data = GeneratePayload(expected_data,
                                               aops,
                                               false,
-                                              kChromeOSMajorPayloadVersion,
+                                              kBrilloMajorPayloadVersion,
                                               kFullPayloadMinorVersion);
 
   EXPECT_EQ(expected_data, ApplyPayload(payload_data, "/dev/null", true));
@@ -469,7 +474,7 @@
   brillo::Blob payload_data = GeneratePayload(expected_data,
                                               aops,
                                               false,
-                                              kChromeOSMajorPayloadVersion,
+                                              kBrilloMajorPayloadVersion,
                                               kFullPayloadMinorVersion);
 
   testing::Mock::VerifyAndClearExpectations(&mock_delegate_);
@@ -725,27 +730,32 @@
 TEST_F(DeltaPerformerTest, ValidateManifestFullGoodTest) {
   // The Manifest we are validating.
   DeltaArchiveManifest manifest;
-  manifest.mutable_new_kernel_info();
-  manifest.mutable_new_rootfs_info();
+  for (const auto& part_name : {"kernel", "rootfs"}) {
+    auto part = manifest.add_partitions();
+    part->set_partition_name(part_name);
+    part->mutable_new_partition_info();
+  }
   manifest.set_minor_version(kFullPayloadMinorVersion);
 
   RunManifestValidation(manifest,
-                        kChromeOSMajorPayloadVersion,
+                        kBrilloMajorPayloadVersion,
                         InstallPayloadType::kFull,
                         ErrorCode::kSuccess);
 }
 
-TEST_F(DeltaPerformerTest, ValidateManifestDeltaGoodTest) {
+TEST_F(DeltaPerformerTest, ValidateManifestDeltaMaxGoodTest) {
   // The Manifest we are validating.
   DeltaArchiveManifest manifest;
-  manifest.mutable_old_kernel_info();
-  manifest.mutable_old_rootfs_info();
-  manifest.mutable_new_kernel_info();
-  manifest.mutable_new_rootfs_info();
+  for (const auto& part_name : {"kernel", "rootfs"}) {
+    auto part = manifest.add_partitions();
+    part->set_partition_name(part_name);
+    part->mutable_old_partition_info();
+    part->mutable_new_partition_info();
+  }
   manifest.set_minor_version(kMaxSupportedMinorPayloadVersion);
 
   RunManifestValidation(manifest,
-                        kChromeOSMajorPayloadVersion,
+                        kBrilloMajorPayloadVersion,
                         InstallPayloadType::kDelta,
                         ErrorCode::kSuccess);
 }
@@ -753,14 +763,16 @@
 TEST_F(DeltaPerformerTest, ValidateManifestDeltaMinGoodTest) {
   // The Manifest we are validating.
   DeltaArchiveManifest manifest;
-  manifest.mutable_old_kernel_info();
-  manifest.mutable_old_rootfs_info();
-  manifest.mutable_new_kernel_info();
-  manifest.mutable_new_rootfs_info();
+  for (const auto& part_name : {"kernel", "rootfs"}) {
+    auto part = manifest.add_partitions();
+    part->set_partition_name(part_name);
+    part->mutable_old_partition_info();
+    part->mutable_new_partition_info();
+  }
   manifest.set_minor_version(kMinSupportedMinorPayloadVersion);
 
   RunManifestValidation(manifest,
-                        kChromeOSMajorPayloadVersion,
+                        kBrilloMajorPayloadVersion,
                         InstallPayloadType::kDelta,
                         ErrorCode::kSuccess);
 }
@@ -778,9 +790,11 @@
 TEST_F(DeltaPerformerTest, ValidateManifestDeltaUnsetMinorVersion) {
   // The Manifest we are validating.
   DeltaArchiveManifest manifest;
-  // Add an empty old_rootfs_info() to trick the DeltaPerformer into think that
-  // this is a delta payload manifest with a missing minor version.
-  manifest.mutable_old_rootfs_info();
+  // Add an empty rootfs partition info to trick the DeltaPerformer into think
+  // that this is a delta payload manifest with a missing minor version.
+  auto rootfs = manifest.add_partitions();
+  rootfs->set_partition_name("rootfs");
+  rootfs->mutable_old_partition_info();
 
   RunManifestValidation(manifest,
                         kMaxSupportedMajorPayloadVersion,
@@ -791,27 +805,15 @@
 TEST_F(DeltaPerformerTest, ValidateManifestFullOldKernelTest) {
   // The Manifest we are validating.
   DeltaArchiveManifest manifest;
-  manifest.mutable_old_kernel_info();
-  manifest.mutable_new_kernel_info();
-  manifest.mutable_new_rootfs_info();
-  manifest.set_minor_version(kMaxSupportedMinorPayloadVersion);
-
+  for (const auto& part_name : {"kernel", "rootfs"}) {
+    auto part = manifest.add_partitions();
+    part->set_partition_name(part_name);
+    part->mutable_old_partition_info();
+    part->mutable_new_partition_info();
+  }
+  manifest.mutable_partitions(0)->clear_old_partition_info();
   RunManifestValidation(manifest,
-                        kChromeOSMajorPayloadVersion,
-                        InstallPayloadType::kFull,
-                        ErrorCode::kPayloadMismatchedType);
-}
-
-TEST_F(DeltaPerformerTest, ValidateManifestFullOldRootfsTest) {
-  // The Manifest we are validating.
-  DeltaArchiveManifest manifest;
-  manifest.mutable_old_rootfs_info();
-  manifest.mutable_new_kernel_info();
-  manifest.mutable_new_rootfs_info();
-  manifest.set_minor_version(kMaxSupportedMinorPayloadVersion);
-
-  RunManifestValidation(manifest,
-                        kChromeOSMajorPayloadVersion,
+                        kBrilloMajorPayloadVersion,
                         InstallPayloadType::kFull,
                         ErrorCode::kPayloadMismatchedType);
 }
@@ -836,8 +838,8 @@
 
   // Generate a bad version number.
   manifest.set_minor_version(kMaxSupportedMinorPayloadVersion + 10000);
-  // Mark the manifest as a delta payload by setting old_rootfs_info.
-  manifest.mutable_old_rootfs_info();
+  // Mark the manifest as a delta payload by setting |old_partition_info|.
+  manifest.add_partitions()->mutable_old_partition_info();
 
   RunManifestValidation(manifest,
                         kMaxSupportedMajorPayloadVersion,
diff --git a/payload_consumer/payload_constants.cc b/payload_consumer/payload_constants.cc
index 9e684d7..908a893 100644
--- a/payload_consumer/payload_constants.cc
+++ b/payload_consumer/payload_constants.cc
@@ -20,9 +20,12 @@
 
 namespace chromeos_update_engine {
 
-const uint64_t kChromeOSMajorPayloadVersion = 1;
+// const uint64_t kChromeOSMajorPayloadVersion = 1;  DEPRECATED
 const uint64_t kBrilloMajorPayloadVersion = 2;
 
+const uint64_t kMinSupportedMajorPayloadVersion = kBrilloMajorPayloadVersion;
+const uint64_t kMaxSupportedMajorPayloadVersion = kBrilloMajorPayloadVersion;
+
 const uint32_t kFullPayloadMinorVersion = 0;
 // const uint32_t kInPlaceMinorPayloadVersion = 1;  DEPRECATED
 const uint32_t kSourceMinorPayloadVersion = 2;
@@ -34,9 +37,6 @@
 const uint32_t kMinSupportedMinorPayloadVersion = kSourceMinorPayloadVersion;
 const uint32_t kMaxSupportedMinorPayloadVersion = kVerityMinorPayloadVersion;
 
-const uint64_t kMinSupportedMajorPayloadVersion = 1;
-const uint64_t kMaxSupportedMajorPayloadVersion = 2;
-
 const uint64_t kMaxPayloadHeaderSize = 24;
 
 const char kPartitionNameKernel[] = "kernel";
diff --git a/payload_consumer/payload_constants.h b/payload_consumer/payload_constants.h
index fe823f4..888fa2a 100644
--- a/payload_consumer/payload_constants.h
+++ b/payload_consumer/payload_constants.h
@@ -26,7 +26,7 @@
 namespace chromeos_update_engine {
 
 // The major version used by Chrome OS.
-extern const uint64_t kChromeOSMajorPayloadVersion;
+// extern const uint64_t kChromeOSMajorPayloadVersion;  DEPRECATED
 
 // The major version used by Brillo.
 extern const uint64_t kBrilloMajorPayloadVersion;
diff --git a/payload_consumer/payload_metadata.cc b/payload_consumer/payload_metadata.cc
index 337edb4..4d8ee7b 100644
--- a/payload_consumer/payload_metadata.cc
+++ b/payload_consumer/payload_metadata.cc
@@ -36,34 +36,18 @@
 const uint64_t PayloadMetadata::kDeltaManifestSizeSize = 8;
 const uint64_t PayloadMetadata::kDeltaMetadataSignatureSizeSize = 4;
 
-bool PayloadMetadata::GetMetadataSignatureSizeOffset(
-    uint64_t* out_offset) const {
-  if (GetMajorVersion() == kBrilloMajorPayloadVersion) {
-    *out_offset = kDeltaManifestSizeOffset + kDeltaManifestSizeSize;
-    return true;
-  }
-  return false;
+uint64_t PayloadMetadata::GetMetadataSignatureSizeOffset() const {
+  return kDeltaManifestSizeOffset + kDeltaManifestSizeSize;
 }
 
-bool PayloadMetadata::GetManifestOffset(uint64_t* out_offset) const {
-  // Actual manifest begins right after the manifest size field or
-  // metadata signature size field if major version >= 2.
-  if (major_payload_version_ == kChromeOSMajorPayloadVersion) {
-    *out_offset = kDeltaManifestSizeOffset + kDeltaManifestSizeSize;
-    return true;
-  }
-  if (major_payload_version_ == kBrilloMajorPayloadVersion) {
-    *out_offset = kDeltaManifestSizeOffset + kDeltaManifestSizeSize +
-                  kDeltaMetadataSignatureSizeSize;
-    return true;
-  }
-  LOG(ERROR) << "Unknown major payload version: " << major_payload_version_;
-  return false;
+uint64_t PayloadMetadata::GetManifestOffset() const {
+  // Actual manifest begins right after the metadata signature size field.
+  return kDeltaManifestSizeOffset + kDeltaManifestSizeSize +
+         kDeltaMetadataSignatureSizeSize;
 }
 
 MetadataParseResult PayloadMetadata::ParsePayloadHeader(
     const brillo::Blob& payload, ErrorCode* error) {
-  uint64_t manifest_offset;
   // Ensure we have data to cover the major payload version.
   if (payload.size() < kDeltaManifestSizeOffset)
     return MetadataParseResult::kInsufficientData;
@@ -75,6 +59,11 @@
     return MetadataParseResult::kError;
   }
 
+  uint64_t manifest_offset = GetManifestOffset();
+  // Check again with the manifest offset.
+  if (payload.size() < manifest_offset)
+    return MetadataParseResult::kInsufficientData;
+
   // Extract the payload version from the metadata.
   static_assert(sizeof(major_payload_version_) == kDeltaVersionSize,
                 "Major payload version size mismatch");
@@ -92,15 +81,6 @@
     return MetadataParseResult::kError;
   }
 
-  // Get the manifest offset now that we have payload version.
-  if (!GetManifestOffset(&manifest_offset)) {
-    *error = ErrorCode::kUnsupportedMajorPayloadVersion;
-    return MetadataParseResult::kError;
-  }
-  // Check again with the manifest offset.
-  if (payload.size() < manifest_offset)
-    return MetadataParseResult::kInsufficientData;
-
   // Next, parse the manifest size.
   static_assert(sizeof(manifest_size_) == kDeltaManifestSizeSize,
                 "manifest_size size mismatch");
@@ -116,26 +96,20 @@
     return MetadataParseResult::kError;
   }
 
-  if (GetMajorVersion() == kBrilloMajorPayloadVersion) {
-    // Parse the metadata signature size.
-    static_assert(
-        sizeof(metadata_signature_size_) == kDeltaMetadataSignatureSizeSize,
-        "metadata_signature_size size mismatch");
-    uint64_t metadata_signature_size_offset;
-    if (!GetMetadataSignatureSizeOffset(&metadata_signature_size_offset)) {
-      *error = ErrorCode::kError;
-      return MetadataParseResult::kError;
-    }
-    memcpy(&metadata_signature_size_,
-           &payload[metadata_signature_size_offset],
-           kDeltaMetadataSignatureSizeSize);
-    metadata_signature_size_ = be32toh(metadata_signature_size_);
+  // Parse the metadata signature size.
+  static_assert(
+      sizeof(metadata_signature_size_) == kDeltaMetadataSignatureSizeSize,
+      "metadata_signature_size size mismatch");
+  uint64_t metadata_signature_size_offset = GetMetadataSignatureSizeOffset();
+  memcpy(&metadata_signature_size_,
+         &payload[metadata_signature_size_offset],
+         kDeltaMetadataSignatureSizeSize);
+  metadata_signature_size_ = be32toh(metadata_signature_size_);
 
-    if (metadata_size_ + metadata_signature_size_ < metadata_size_) {
-      // Overflow detected.
-      *error = ErrorCode::kDownloadInvalidMetadataSize;
-      return MetadataParseResult::kError;
-    }
+  if (metadata_size_ + metadata_signature_size_ < metadata_size_) {
+    // Overflow detected.
+    *error = ErrorCode::kDownloadInvalidMetadataSize;
+    return MetadataParseResult::kError;
   }
   return MetadataParseResult::kSuccess;
 }
@@ -147,9 +121,7 @@
 
 bool PayloadMetadata::GetManifest(const brillo::Blob& payload,
                                   DeltaArchiveManifest* out_manifest) const {
-  uint64_t manifest_offset;
-  if (!GetManifestOffset(&manifest_offset))
-    return false;
+  uint64_t manifest_offset = GetManifestOffset();
   CHECK_GE(payload.size(), manifest_offset + manifest_size_);
   return out_manifest->ParseFromArray(&payload[manifest_offset],
                                       manifest_size_);
@@ -171,7 +143,7 @@
                  << metadata_signature;
       return ErrorCode::kDownloadMetadataSignatureError;
     }
-  } else if (major_payload_version_ == kBrilloMajorPayloadVersion) {
+  } else {
     metadata_signature_protobuf_blob.assign(
         payload.begin() + metadata_size_,
         payload.begin() + metadata_size_ + metadata_signature_size_);
@@ -243,8 +215,7 @@
     TEST_AND_RETURN_FALSE(GetManifest(payload, manifest));
   }
 
-  if (metadata_signatures != nullptr &&
-      GetMajorVersion() >= kBrilloMajorPayloadVersion) {
+  if (metadata_signatures != nullptr) {
     payload.clear();
     TEST_AND_RETURN_FALSE(utils::ReadFileChunk(
         payload_path, GetMetadataSize(), GetMetadataSignatureSize(), &payload));
diff --git a/payload_consumer/payload_metadata.h b/payload_consumer/payload_metadata.h
index ec8eea6..be43c41 100644
--- a/payload_consumer/payload_metadata.h
+++ b/payload_consumer/payload_metadata.h
@@ -94,14 +94,12 @@
                         Signatures* metadata_signatures);
 
  private:
-  // Set |*out_offset| to the byte offset at which the manifest protobuf begins
-  // in a payload. Return true on success, false if the offset is unknown.
-  bool GetManifestOffset(uint64_t* out_offset) const;
+  // Returns the byte offset at which the manifest protobuf begins in a payload.
+  uint64_t GetManifestOffset() const;
 
-  // Set |*out_offset| to the byte offset where the size of the metadata
-  // signature is stored in a payload. Return true on success, if this field is
-  // not present in the payload, return false.
-  bool GetMetadataSignatureSizeOffset(uint64_t* out_offset) const;
+  // Returns the byte offset where the size of the metadata signature is stored
+  // in a payload.
+  uint64_t GetMetadataSignatureSizeOffset() const;
 
   uint64_t metadata_size_{0};
   uint64_t manifest_size_{0};