diff --git a/common/test_utils.cc b/common/test_utils.cc
index 4d1e20d..c09096b 100644
--- a/common/test_utils.cc
+++ b/common/test_utils.cc
@@ -35,6 +35,7 @@
 #include <base/strings/string_util.h>
 #include <base/strings/stringprintf.h>
 
+#include "update_engine/common/error_code_utils.h"
 #include "update_engine/common/utils.h"
 #include "update_engine/payload_consumer/file_writer.h"
 
@@ -49,6 +50,10 @@
   *os << "(" << extent.start_block() << ", " << extent.num_blocks() << ")";
 }
 
+void PrintTo(const ErrorCode& error_code, ::std::ostream* os) {
+  *os << utils::ErrorCodeToString(error_code);
+}
+
 namespace test_utils {
 
 const char* const kMountPathTemplate = "UpdateEngineTests_mnt-XXXXXX";
diff --git a/common/test_utils.h b/common/test_utils.h
index 616bdd3..b5151f2 100644
--- a/common/test_utils.h
+++ b/common/test_utils.h
@@ -44,6 +44,7 @@
 // PrintTo() functions are used by gtest to log these objects. These PrintTo()
 // functions must be defined in the same namespace as the first argument.
 void PrintTo(const Extent& extent, ::std::ostream* os);
+void PrintTo(const ErrorCode& error_code, ::std::ostream* os);
 
 namespace test_utils {
 
diff --git a/omaha_response_handler_action.cc b/omaha_response_handler_action.cc
index 9a449eb..33380d7 100644
--- a/omaha_response_handler_action.cc
+++ b/omaha_response_handler_action.cc
@@ -104,7 +104,9 @@
         kPrefsUpdateCheckResponseHash, response.hash))
         << "Unable to save the update check response hash.";
   }
-  install_plan_.is_full_update = !response.is_delta_payload;
+  install_plan_.payload_type = response.is_delta_payload
+                                   ? InstallPayloadType::kDelta
+                                   : InstallPayloadType::kFull;
 
   install_plan_.source_slot = system_state_->boot_control()->GetCurrentSlot();
   install_plan_.target_slot = install_plan_.source_slot == 0 ? 1 : 0;
diff --git a/payload_consumer/delta_performer.cc b/payload_consumer/delta_performer.cc
index 09304e4..cb3cdb5 100644
--- a/payload_consumer/delta_performer.cc
+++ b/payload_consumer/delta_performer.cc
@@ -291,7 +291,7 @@
 
   const PartitionUpdate& partition = partitions_[current_partition_];
   // Open source fds if we have a delta payload with minor version >= 2.
-  if (!install_plan_->is_full_update &&
+  if (install_plan_->payload_type == InstallPayloadType::kDelta &&
       GetMinorVersion() != kInPlaceMinorPayloadVersion) {
     source_path_ = install_plan_->partitions[current_partition_].source_path;
     int err;
@@ -374,9 +374,9 @@
   if (manifest_.has_minor_version()) {
     return manifest_.minor_version();
   } else {
-    return (install_plan_->is_full_update ?
-            kFullPayloadMinorVersion :
-            kSupportedMinorPayloadVersion);
+    return install_plan_->payload_type == InstallPayloadType::kDelta
+               ? kSupportedMinorPayloadVersion
+               : kFullPayloadMinorVersion;
   }
 }
 
@@ -1362,29 +1362,34 @@
 ErrorCode DeltaPerformer::ValidateManifest() {
   // Perform assorted checks to sanity check the manifest, make sure it
   // matches data from other sources, and that it is a supported version.
-  //
-  // TODO(garnold) in general, the presence of an old partition hash should be
-  // the sole indicator for a delta update, as we would generally like update
-  // payloads to be self contained and not assume an Omaha response to tell us
-  // that. However, since this requires some massive reengineering of the update
-  // flow (making filesystem copying happen conditionally only *after*
-  // downloading and parsing of the update manifest) we'll put it off for now.
-  // See chromium-os:7597 for further discussion.
-  if (install_plan_->is_full_update) {
-    if (manifest_.has_old_kernel_info() || manifest_.has_old_rootfs_info()) {
-      LOG(ERROR) << "Purported full payload contains old partition "
-                    "hash(es), aborting update";
-      return ErrorCode::kPayloadMismatchedType;
-    }
 
-    for (const PartitionUpdate& partition : manifest_.partitions()) {
-      if (partition.has_old_partition_info()) {
-        LOG(ERROR) << "Purported full payload contains old partition "
-                      "hash(es), aborting update";
-        return ErrorCode::kPayloadMismatchedType;
-      }
-    }
+  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();
+  }
 
+  // The presence of an old partition hash is the sole indicator for a delta
+  // update.
+  InstallPayloadType actual_payload_type =
+      has_old_fields ? InstallPayloadType::kDelta : InstallPayloadType::kFull;
+
+  if (install_plan_->payload_type == InstallPayloadType::kUnknown) {
+    LOG(INFO) << "Detected a '"
+              << InstallPayloadTypeToString(actual_payload_type)
+              << "' payload.";
+    install_plan_->payload_type = actual_payload_type;
+  } else if (install_plan_->payload_type != actual_payload_type) {
+    LOG(ERROR) << "InstallPlan expected a '"
+               << InstallPayloadTypeToString(install_plan_->payload_type)
+               << "' payload but the downloaded manifest contains a '"
+               << InstallPayloadTypeToString(actual_payload_type)
+               << "' payload.";
+    return ErrorCode::kPayloadMismatchedType;
+  }
+
+  // Check that the minor version is compatible.
+  if (actual_payload_type == InstallPayloadType::kFull) {
     if (manifest_.minor_version() != kFullPayloadMinorVersion) {
       LOG(ERROR) << "Manifest contains minor version "
                  << manifest_.minor_version()
diff --git a/payload_consumer/delta_performer_integration_test.cc b/payload_consumer/delta_performer_integration_test.cc
index 65d685d..9b7854b 100644
--- a/payload_consumer/delta_performer_integration_test.cc
+++ b/payload_consumer/delta_performer_integration_test.cc
@@ -715,7 +715,9 @@
   InstallPlan* install_plan = &state->install_plan;
   install_plan->hash_checks_mandatory = hash_checks_mandatory;
   install_plan->metadata_size = state->metadata_size;
-  install_plan->is_full_update = full_kernel && full_rootfs;
+  install_plan->payload_type = (full_kernel && full_rootfs)
+                                   ? InstallPayloadType::kFull
+                                   : InstallPayloadType::kDelta;
   install_plan->source_slot = 0;
   install_plan->target_slot = 1;
 
diff --git a/payload_consumer/delta_performer_unittest.cc b/payload_consumer/delta_performer_unittest.cc
index fa904f2..dabe138 100644
--- a/payload_consumer/delta_performer_unittest.cc
+++ b/payload_consumer/delta_performer_unittest.cc
@@ -97,10 +97,9 @@
   // Test helper placed where it can easily be friended from DeltaPerformer.
   void RunManifestValidation(const DeltaArchiveManifest& manifest,
                              uint64_t major_version,
-                             bool full_payload,
+                             InstallPayloadType payload_type,
                              ErrorCode expected) {
-    // The install plan is for Full or Delta.
-    install_plan_.is_full_update = full_payload;
+    install_plan_.payload_type = payload_type;
 
     // The Manifest we are validating.
     performer_.manifest_.CopyFrom(manifest);
@@ -137,6 +136,12 @@
     EXPECT_TRUE(payload.Init(config));
 
     PartitionConfig old_part(kLegacyPartitionNameRoot);
+    if (minor_version != kFullPayloadMinorVersion) {
+      // When generating a delta payload we need to include the old partition
+      // information to mark it as a delta payload.
+      old_part.path = "/dev/null";
+      old_part.size = 0;
+    }
     PartitionConfig new_part(kLegacyPartitionNameRoot);
     new_part.path = "/dev/zero";
     new_part.size = 1234;
@@ -323,7 +328,7 @@
 };
 
 TEST_F(DeltaPerformerTest, FullPayloadWriteTest) {
-  install_plan_.is_full_update = true;
+  install_plan_.payload_type = InstallPayloadType::kFull;
   brillo::Blob expected_data = brillo::Blob(std::begin(kRandomString),
                                             std::end(kRandomString));
   expected_data.resize(4096);  // block size
@@ -342,7 +347,7 @@
 }
 
 TEST_F(DeltaPerformerTest, ShouldCancelTest) {
-  install_plan_.is_full_update = true;
+  install_plan_.payload_type = InstallPayloadType::kFull;
   brillo::Blob expected_data = brillo::Blob(std::begin(kRandomString),
                                             std::end(kRandomString));
   expected_data.resize(4096);  // block size
@@ -522,7 +527,9 @@
   manifest.mutable_new_rootfs_info();
   manifest.set_minor_version(kFullPayloadMinorVersion);
 
-  RunManifestValidation(manifest, kChromeOSMajorPayloadVersion, true,
+  RunManifestValidation(manifest,
+                        kChromeOSMajorPayloadVersion,
+                        InstallPayloadType::kFull,
                         ErrorCode::kSuccess);
 }
 
@@ -535,7 +542,9 @@
   manifest.mutable_new_rootfs_info();
   manifest.set_minor_version(DeltaPerformer::kSupportedMinorPayloadVersion);
 
-  RunManifestValidation(manifest, kChromeOSMajorPayloadVersion, false,
+  RunManifestValidation(manifest,
+                        kChromeOSMajorPayloadVersion,
+                        InstallPayloadType::kDelta,
                         ErrorCode::kSuccess);
 }
 
@@ -543,16 +552,23 @@
   // The Manifest we are validating.
   DeltaArchiveManifest manifest;
 
-  RunManifestValidation(manifest, DeltaPerformer::kSupportedMajorPayloadVersion,
-                        true, ErrorCode::kSuccess);
+  RunManifestValidation(manifest,
+                        DeltaPerformer::kSupportedMajorPayloadVersion,
+                        InstallPayloadType::kFull,
+                        ErrorCode::kSuccess);
 }
 
 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();
 
-  RunManifestValidation(manifest, DeltaPerformer::kSupportedMajorPayloadVersion,
-                        false, ErrorCode::kUnsupportedMinorPayloadVersion);
+  RunManifestValidation(manifest,
+                        DeltaPerformer::kSupportedMajorPayloadVersion,
+                        InstallPayloadType::kDelta,
+                        ErrorCode::kUnsupportedMinorPayloadVersion);
 }
 
 TEST_F(DeltaPerformerTest, ValidateManifestFullOldKernelTest) {
@@ -563,7 +579,9 @@
   manifest.mutable_new_rootfs_info();
   manifest.set_minor_version(DeltaPerformer::kSupportedMinorPayloadVersion);
 
-  RunManifestValidation(manifest, kChromeOSMajorPayloadVersion, true,
+  RunManifestValidation(manifest,
+                        kChromeOSMajorPayloadVersion,
+                        InstallPayloadType::kFull,
                         ErrorCode::kPayloadMismatchedType);
 }
 
@@ -575,7 +593,9 @@
   manifest.mutable_new_rootfs_info();
   manifest.set_minor_version(DeltaPerformer::kSupportedMinorPayloadVersion);
 
-  RunManifestValidation(manifest, kChromeOSMajorPayloadVersion, true,
+  RunManifestValidation(manifest,
+                        kChromeOSMajorPayloadVersion,
+                        InstallPayloadType::kFull,
                         ErrorCode::kPayloadMismatchedType);
 }
 
@@ -587,7 +607,9 @@
   partition->mutable_new_partition_info();
   manifest.set_minor_version(DeltaPerformer::kSupportedMinorPayloadVersion);
 
-  RunManifestValidation(manifest, kBrilloMajorPayloadVersion, true,
+  RunManifestValidation(manifest,
+                        kBrilloMajorPayloadVersion,
+                        InstallPayloadType::kFull,
                         ErrorCode::kPayloadMismatchedType);
 }
 
@@ -598,9 +620,13 @@
   // Generate a bad version number.
   manifest.set_minor_version(DeltaPerformer::kSupportedMinorPayloadVersion +
                              10000);
+  // Mark the manifest as a delta payload by setting old_rootfs_info.
+  manifest.mutable_old_rootfs_info();
 
-  RunManifestValidation(manifest, DeltaPerformer::kSupportedMajorPayloadVersion,
-                        false, ErrorCode::kUnsupportedMinorPayloadVersion);
+  RunManifestValidation(manifest,
+                        DeltaPerformer::kSupportedMajorPayloadVersion,
+                        InstallPayloadType::kDelta,
+                        ErrorCode::kUnsupportedMinorPayloadVersion);
 }
 
 TEST_F(DeltaPerformerTest, BrilloMetadataSignatureSizeTest) {
diff --git a/payload_consumer/download_action_unittest.cc b/payload_consumer/download_action_unittest.cc
index 60cc6f2..979776f 100644
--- a/payload_consumer/download_action_unittest.cc
+++ b/payload_consumer/download_action_unittest.cc
@@ -143,14 +143,10 @@
   // We pull off the first byte from data and seek past it.
   string hash = HashCalculator::HashOfBytes(&data[1], data.size() - 1);
   uint64_t size = data.size();
-  InstallPlan install_plan(false,
-                           false,
-                           "",
-                           size,
-                           hash,
-                           0,
-                           "",
-                           "");
+  InstallPlan install_plan;
+  install_plan.payload_type = InstallPayloadType::kDelta;
+  install_plan.payload_size = size;
+  install_plan.payload_hash = hash;
   install_plan.source_slot = 0;
   install_plan.target_slot = 1;
   // We mark both slots as bootable. Only the target slot should be unbootable
@@ -278,7 +274,7 @@
 
     // takes ownership of passed in HttpFetcher
     ObjectFeederAction<InstallPlan> feeder_action;
-    InstallPlan install_plan(false, false, "", 0, "", 0, "", "");
+    InstallPlan install_plan;
     feeder_action.set_obj(install_plan);
     FakeSystemState fake_system_state_;
     MockPrefs prefs;
@@ -375,14 +371,9 @@
   EXPECT_EQ(0, writer.Open("/dev/null", O_WRONLY | O_CREAT, 0));
 
   // takes ownership of passed in HttpFetcher
-  InstallPlan install_plan(false,
-                           false,
-                           "",
-                           1,
-                           HashCalculator::HashOfString("x"),
-                           0,
-                           "",
-                           "");
+  InstallPlan install_plan;
+  install_plan.payload_size = 1;
+  install_plan.payload_hash = HashCalculator::HashOfString("x");
   ObjectFeederAction<InstallPlan> feeder_action;
   feeder_action.set_obj(install_plan);
   MockPrefs prefs;
@@ -463,14 +454,9 @@
     EXPECT_EQ(0, writer.Open(output_temp_file.GetPath().c_str(),
                              O_WRONLY | O_CREAT,
                              0));
-    InstallPlan install_plan(false,
-                             false,
-                             "",
-                             data_.length(),
-                             "1234hash",
-                             0,
-                             "",
-                             "");
+    InstallPlan install_plan;
+    install_plan.payload_size = data_.length();
+    install_plan.payload_hash = "1234hash";
     ObjectFeederAction<InstallPlan> feeder_action;
     feeder_action.set_obj(install_plan);
     MockPrefs prefs;
diff --git a/payload_consumer/filesystem_verifier_action.cc b/payload_consumer/filesystem_verifier_action.cc
index 8530d37..759b455 100644
--- a/payload_consumer/filesystem_verifier_action.cc
+++ b/payload_consumer/filesystem_verifier_action.cc
@@ -59,7 +59,8 @@
 
   // For delta updates (major version 1) we need to populate the source
   // partition hash if not pre-populated.
-  if (!install_plan_.is_full_update && install_plan_.partitions.empty() &&
+  if (install_plan_.payload_type == InstallPayloadType::kDelta &&
+      install_plan_.partitions.empty() &&
       verifier_mode_ == VerifierMode::kComputeSourceHash &&
       DeltaPerformer::kSupportedMinorPayloadVersion <
           kOpSrcHashMinorPayloadVersion) {
diff --git a/payload_consumer/filesystem_verifier_action_unittest.cc b/payload_consumer/filesystem_verifier_action_unittest.cc
index 0b6232b..10daaa8 100644
--- a/payload_consumer/filesystem_verifier_action_unittest.cc
+++ b/payload_consumer/filesystem_verifier_action_unittest.cc
@@ -285,14 +285,7 @@
   processor.set_delegate(&delegate);
 
   ObjectFeederAction<InstallPlan> feeder_action;
-  InstallPlan install_plan(false,
-                           false,
-                           "",
-                           0,
-                           "",
-                           0,
-                           "",
-                           "");
+  InstallPlan install_plan;
   InstallPlan::Partition part;
   part.name = "nope";
   part.source_path = "/no/such/file";
diff --git a/payload_consumer/install_plan.cc b/payload_consumer/install_plan.cc
index a2a1b7b..572ff41 100644
--- a/payload_consumer/install_plan.cc
+++ b/payload_consumer/install_plan.cc
@@ -27,29 +27,21 @@
 
 namespace chromeos_update_engine {
 
-InstallPlan::InstallPlan(bool is_resume,
-                         bool is_full_update,
-                         const string& url,
-                         uint64_t payload_size,
-                         const string& payload_hash,
-                         uint64_t metadata_size,
-                         const string& metadata_signature,
-                         const string& public_key_rsa)
-    : is_resume(is_resume),
-      is_full_update(is_full_update),
-      download_url(url),
-      payload_size(payload_size),
-      payload_hash(payload_hash),
-      metadata_size(metadata_size),
-      metadata_signature(metadata_signature),
-      hash_checks_mandatory(false),
-      powerwash_required(false),
-      public_key_rsa(public_key_rsa) {}
-
+string InstallPayloadTypeToString(InstallPayloadType type) {
+  switch (type) {
+    case InstallPayloadType::kUnknown:
+      return "unknown";
+    case InstallPayloadType::kFull:
+      return "full";
+    case InstallPayloadType::kDelta:
+      return "delta";
+  }
+  return "invalid type";
+}
 
 bool InstallPlan::operator==(const InstallPlan& that) const {
   return ((is_resume == that.is_resume) &&
-          (is_full_update == that.is_full_update) &&
+          (payload_type == that.payload_type) &&
           (download_url == that.download_url) &&
           (payload_size == that.payload_size) &&
           (payload_hash == that.payload_hash) &&
@@ -74,7 +66,7 @@
 
   LOG(INFO) << "InstallPlan: "
             << (is_resume ? "resume" : "new_update")
-            << ", payload type: " << (is_full_update ? "full" : "delta")
+            << ", payload type: " << InstallPayloadTypeToString(payload_type)
             << ", source_slot: " << BootControlInterface::SlotName(source_slot)
             << ", target_slot: " << BootControlInterface::SlotName(target_slot)
             << ", url: " << download_url
@@ -85,8 +77,7 @@
             << partitions_str
             << ", hash_checks_mandatory: " << utils::ToString(
                 hash_checks_mandatory)
-            << ", powerwash_required: " << utils::ToString(
-                powerwash_required);
+            << ", powerwash_required: " << utils::ToString(powerwash_required);
 }
 
 bool InstallPlan::LoadPartitionsFromSlots(BootControlInterface* boot_control) {
diff --git a/payload_consumer/install_plan.h b/payload_consumer/install_plan.h
index e69462d..d2f15fa 100644
--- a/payload_consumer/install_plan.h
+++ b/payload_consumer/install_plan.h
@@ -30,17 +30,15 @@
 // parts of the update system about the install that should happen.
 namespace chromeos_update_engine {
 
-struct InstallPlan {
-  InstallPlan(bool is_resume,
-              bool is_full_update,
-              const std::string& url,
-              uint64_t payload_size,
-              const std::string& payload_hash,
-              uint64_t metadata_size,
-              const std::string& metadata_signature,
-              const std::string& public_key_rsa);
+enum class InstallPayloadType {
+  kUnknown,
+  kFull,
+  kDelta,
+};
 
-  // Default constructor.
+std::string InstallPayloadTypeToString(InstallPayloadType type);
+
+struct InstallPlan {
   InstallPlan() = default;
 
   bool operator==(const InstallPlan& that) const;
@@ -54,7 +52,7 @@
   bool LoadPartitionsFromSlots(BootControlInterface* boot_control);
 
   bool is_resume{false};
-  bool is_full_update{false};
+  InstallPayloadType payload_type{InstallPayloadType::kUnknown};
   std::string download_url;  // url to download from
   std::string version;       // version we are installing.
 
diff --git a/update_attempter_android.cc b/update_attempter_android.cc
index 90501fb..cc478a4 100644
--- a/update_attempter_android.cc
+++ b/update_attempter_android.cc
@@ -159,8 +159,8 @@
       LOG(WARNING) << "Unable to save the update check response hash.";
     }
   }
-  // The |is_full_update| is not used anymore since minor_version 3.
-  install_plan_.is_full_update = true;
+  // The |payload_type| is not used anymore since minor_version 3.
+  install_plan_.payload_type = InstallPayloadType::kUnknown;
 
   install_plan_.source_slot = boot_control_->GetCurrentSlot();
   install_plan_.target_slot = install_plan_.source_slot == 0 ? 1 : 0;