diff --git a/fs_mgr/libsnapshot/snapshot.cpp b/fs_mgr/libsnapshot/snapshot.cpp
index 81d3cbc..63d97d0 100644
--- a/fs_mgr/libsnapshot/snapshot.cpp
+++ b/fs_mgr/libsnapshot/snapshot.cpp
@@ -1793,6 +1793,14 @@
     auto target_metadata =
             MetadataBuilder::NewForUpdate(opener, current_super, current_slot, target_slot);
 
+    // Delete partitions with target suffix in |current_metadata|. Otherwise,
+    // partition_cow_creator recognizes these left-over partitions as used space.
+    for (const auto& group_name : current_metadata->ListGroups()) {
+        if (android::base::EndsWith(group_name, target_suffix)) {
+            current_metadata->RemoveGroupAndPartitions(group_name);
+        }
+    }
+
     SnapshotMetadataUpdater metadata_updater(target_metadata.get(), target_slot, manifest);
     if (!metadata_updater.Update()) {
         LOG(ERROR) << "Cannot calculate new metadata.";
diff --git a/fs_mgr/libsnapshot/snapshot_test.cpp b/fs_mgr/libsnapshot/snapshot_test.cpp
index 9138fc3..2161e5b 100644
--- a/fs_mgr/libsnapshot/snapshot_test.cpp
+++ b/fs_mgr/libsnapshot/snapshot_test.cpp
@@ -57,6 +57,7 @@
 using android::fs_mgr::Interval;
 using android::fs_mgr::MetadataBuilder;
 using chromeos_update_engine::DeltaArchiveManifest;
+using chromeos_update_engine::DynamicPartitionGroup;
 using chromeos_update_engine::PartitionUpdate;
 using namespace ::testing;
 using namespace android::storage_literals;
@@ -660,12 +661,12 @@
         // Not using full name "system", "vendor", "product" because these names collide with the
         // mapped partitions on the running device.
         // Each test modifies manifest_ slightly to indicate changes to the partition layout.
-        auto group = manifest_.mutable_dynamic_partition_metadata()->add_groups();
-        group->set_name("group");
-        group->set_size(kGroupSize);
-        group->add_partition_names("sys");
-        group->add_partition_names("vnd");
-        group->add_partition_names("prd");
+        group_ = manifest_.mutable_dynamic_partition_metadata()->add_groups();
+        group_->set_name("group");
+        group_->set_size(kGroupSize);
+        group_->add_partition_names("sys");
+        group_->add_partition_names("vnd");
+        group_->add_partition_names("prd");
         sys_ = manifest_.add_partitions();
         sys_->set_partition_name("sys");
         SetSize(sys_, 3_MiB);
@@ -769,6 +770,7 @@
     PartitionUpdate* sys_ = nullptr;
     PartitionUpdate* vnd_ = nullptr;
     PartitionUpdate* prd_ = nullptr;
+    DynamicPartitionGroup* group_ = nullptr;
 };
 
 // Test full update flow executed by update_engine. Some partitions uses super empty space,
@@ -1060,6 +1062,91 @@
     }
 }
 
+TEST_F(SnapshotUpdateTest, RetrofitAfterRegularAb) {
+    constexpr auto kRetrofitGroupSize = kGroupSize / 2;
+
+    // Initialize device-mapper / disk
+    ASSERT_TRUE(UnmapAll());
+    FormatFakeSuper();
+
+    // Setup source partition metadata to have both _a and _b partitions.
+    src_ = MetadataBuilder::New(*opener_, "super", 0);
+    ASSERT_NE(nullptr, src_);
+    for (const auto& suffix : {"_a"s, "_b"s}) {
+        ASSERT_TRUE(src_->AddGroup(group_->name() + suffix, kRetrofitGroupSize));
+        for (const auto& name : {"sys"s, "vnd"s, "prd"s}) {
+            auto partition = src_->AddPartition(name + suffix, group_->name() + suffix, 0);
+            ASSERT_NE(nullptr, partition);
+            ASSERT_TRUE(src_->ResizePartition(partition, 2_MiB));
+        }
+    }
+    auto metadata = src_->Export();
+    ASSERT_NE(nullptr, metadata);
+    ASSERT_TRUE(UpdatePartitionTable(*opener_, "super", *metadata.get(), 0));
+
+    // Flash source partitions
+    std::string path;
+    for (const auto& name : {"sys_a", "vnd_a", "prd_a"}) {
+        ASSERT_TRUE(CreateLogicalPartition(
+                CreateLogicalPartitionParams{
+                        .block_device = fake_super,
+                        .metadata_slot = 0,
+                        .partition_name = name,
+                        .timeout_ms = 1s,
+                        .partition_opener = opener_.get(),
+                },
+                &path));
+        ASSERT_TRUE(WriteRandomData(path));
+        auto hash = GetHash(path);
+        ASSERT_TRUE(hash.has_value());
+        hashes_[name] = *hash;
+    }
+
+    // Setup manifest.
+    group_->set_size(kRetrofitGroupSize);
+    for (auto* partition : {sys_, vnd_, prd_}) {
+        SetSize(partition, 2_MiB);
+        auto* e = partition->add_operations()->add_dst_extents();
+        e->set_start_block(0);
+        e->set_num_blocks(2_MiB / manifest_.block_size());
+    }
+
+    ASSERT_TRUE(sm->BeginUpdate());
+    ASSERT_TRUE(sm->CreateUpdateSnapshots(manifest_));
+
+    // Test that COW image should not be created for retrofit devices; super
+    // should be big enough.
+    ASSERT_FALSE(image_manager_->BackingImageExists("sys_b-cow-img"));
+    ASSERT_FALSE(image_manager_->BackingImageExists("vnd_b-cow-img"));
+    ASSERT_FALSE(image_manager_->BackingImageExists("prd_b-cow-img"));
+
+    // Write some data to target partitions.
+    for (const auto& name : {"sys_b", "vnd_b", "prd_b"}) {
+        std::string path;
+        ASSERT_TRUE(sm->MapUpdateSnapshot(
+                CreateLogicalPartitionParams{
+                        .block_device = fake_super,
+                        .metadata_slot = 1,
+                        .partition_name = name,
+                        .timeout_ms = 10s,
+                        .partition_opener = opener_.get(),
+                },
+                &path))
+                << name;
+        ASSERT_TRUE(WriteRandomData(path));
+        auto hash = GetHash(path);
+        ASSERT_TRUE(hash.has_value());
+        hashes_[name] = *hash;
+    }
+
+    // Assert that source partitions aren't affected.
+    for (const auto& name : {"sys_a", "vnd_a", "prd_a"}) {
+        ASSERT_TRUE(IsPartitionUnchanged(name));
+    }
+
+    ASSERT_TRUE(sm->FinishedSnapshotWrites());
+}
+
 class MetadataMountedTest : public SnapshotUpdateTest {
   public:
     void SetUp() override {