diff --git a/debuggerd/crasher/arm/crashglue.S b/debuggerd/crasher/arm/crashglue.S
index 0def8ae..3001ca1 100644
--- a/debuggerd/crasher/arm/crashglue.S
+++ b/debuggerd/crasher/arm/crashglue.S
@@ -1,3 +1,19 @@
+/*
+ * Copyright 2006, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 .globl crash1
 .type crash1, %function
 crash1:
diff --git a/debuggerd/crasher/arm64/crashglue.S b/debuggerd/crasher/arm64/crashglue.S
index c56e19a..90ba9a1 100644
--- a/debuggerd/crasher/arm64/crashglue.S
+++ b/debuggerd/crasher/arm64/crashglue.S
@@ -1,3 +1,19 @@
+/*
+ * Copyright 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 .globl crash1
 .type crash1, %function
 crash1:
diff --git a/debuggerd/crasher/riscv64/crashglue.S b/debuggerd/crasher/riscv64/crashglue.S
index f179e33..804a511 100644
--- a/debuggerd/crasher/riscv64/crashglue.S
+++ b/debuggerd/crasher/riscv64/crashglue.S
@@ -1,3 +1,19 @@
+/*
+ * Copyright 2022, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 .globl crash1
 crash1:
 	.cfi_startproc
diff --git a/debuggerd/crasher/x86/crashglue.S b/debuggerd/crasher/x86/crashglue.S
index 453035b..fe7c648 100644
--- a/debuggerd/crasher/x86/crashglue.S
+++ b/debuggerd/crasher/x86/crashglue.S
@@ -1,3 +1,19 @@
+/*
+ * Copyright 2010, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 .globl crash1
 crash1:
 	movl $0xa5a50000, %eax
diff --git a/debuggerd/crasher/x86_64/crashglue.S b/debuggerd/crasher/x86_64/crashglue.S
index c3d39c4..ae13aa7 100644
--- a/debuggerd/crasher/x86_64/crashglue.S
+++ b/debuggerd/crasher/x86_64/crashglue.S
@@ -1,3 +1,19 @@
+/*
+ * Copyright 2010, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 .globl crash1
 crash1:
 	movl $0xa5a50000, %eax
diff --git a/fastboot/fastboot.cpp b/fastboot/fastboot.cpp
index 3ce8141..b12e584 100644
--- a/fastboot/fastboot.cpp
+++ b/fastboot/fastboot.cpp
@@ -1525,7 +1525,7 @@
         fb->ResizePartition(pname, std::to_string(buf.image_size));
     }
     std::string flash_pname = repack_ramdisk(pname, &buf, fp->fb);
-    flash_buf(fp->source, flash_pname, &buf, apply_vbmeta);
+    flash_buf(fp->source.get(), flash_pname, &buf, apply_vbmeta);
 }
 
 // Sets slot_override as the active slot. If slot_override is blank,
@@ -1679,7 +1679,7 @@
     }
     for (size_t i = 0; i < tasks->size(); i++) {
         if (auto flash_task = tasks->at(i)->AsFlashTask()) {
-            if (FlashTask::IsDynamicParitition(fp->source, flash_task)) {
+            if (FlashTask::IsDynamicParitition(fp->source.get(), flash_task)) {
                 if (!loc) {
                     loc = i;
                 }
@@ -1810,7 +1810,8 @@
     if (fp_->exclude_dynamic_partitions) {
         auto is_non_static_flash_task = [&](const auto& task) -> bool {
             if (auto flash_task = task->AsFlashTask()) {
-                if (!should_flash_in_userspace(fp_->source, flash_task->GetPartitionAndSlot())) {
+                if (!should_flash_in_userspace(fp_->source.get(),
+                                               flash_task->GetPartitionAndSlot())) {
                     return false;
                 }
             }
@@ -1884,9 +1885,10 @@
         // On these devices, secondary slots must be flashed as physical
         // partitions (otherwise they would not mount on first boot). To enforce
         // this, we delete any logical partitions for the "other" slot.
-        if (is_retrofit_device(fp_->source)) {
+        if (is_retrofit_device(fp_->source.get())) {
             std::string partition_name = image->part_name + "_" + slot;
-            if (image->IsSecondary() && should_flash_in_userspace(fp_->source, partition_name)) {
+            if (image->IsSecondary() &&
+                should_flash_in_userspace(fp_->source.get(), partition_name)) {
                 tasks.emplace_back(std::make_unique<DeleteTask>(fp_, partition_name));
             }
         }
@@ -1949,8 +1951,7 @@
     if (error != 0) {
         die("failed to open zip file '%s': %s", filename, ErrorCodeString(error));
     }
-    ZipImageSource zp = ZipImageSource(zip);
-    fp->source = &zp;
+    fp->source.reset(new ZipImageSource(zip));
     FlashAllTool tool(fp);
     tool.Flash();
 
@@ -1971,8 +1972,7 @@
 }
 
 static void do_flashall(FlashingPlan* fp) {
-    LocalImageSource s = LocalImageSource();
-    fp->source = &s;
+    fp->source.reset(new LocalImageSource());
     FlashAllTool tool(fp);
     tool.Flash();
 }
@@ -2089,7 +2089,7 @@
         die("Cannot read image: %s", strerror(errno));
     }
 
-    flash_buf(fp->source, partition, &buf, is_vbmeta_partition(partition));
+    flash_buf(fp->source.get(), partition, &buf, is_vbmeta_partition(partition));
     return;
 
 failed:
diff --git a/fastboot/fastboot.h b/fastboot/fastboot.h
index 4859ceb..cd7bc2d 100644
--- a/fastboot/fastboot.h
+++ b/fastboot/fastboot.h
@@ -28,6 +28,7 @@
 #pragma once
 
 #include <functional>
+#include <memory>
 #include <string>
 #include "fastboot_driver_interface.h"
 #include "filesystem.h"
@@ -89,7 +90,7 @@
     // If the image uses the default slot, or the user specified "all", then
     // the paired string will be empty. If the image requests a specific slot
     // (for example, system_other) it is specified instead.
-    ImageSource* source;
+    std::unique_ptr<ImageSource> source;
     bool wants_wipe = false;
     bool skip_reboot = false;
     bool wants_set_active = false;
diff --git a/fastboot/task.cpp b/fastboot/task.cpp
index 4b2b9e3..25c5a6e 100644
--- a/fastboot/task.cpp
+++ b/fastboot/task.cpp
@@ -41,7 +41,7 @@
 
 void FlashTask::Run() {
     auto flash = [&](const std::string& partition) {
-        if (should_flash_in_userspace(fp_->source, partition) && !is_userspace_fastboot() &&
+        if (should_flash_in_userspace(fp_->source.get(), partition) && !is_userspace_fastboot() &&
             !fp_->force_flash) {
             die("The partition you are trying to flash is dynamic, and "
                 "should be flashed via fastbootd. Please run:\n"
@@ -174,7 +174,7 @@
         LOG(VERBOSE) << "Cannot optimize flashing super for all slots";
         return nullptr;
     }
-    if (!CanOptimize(fp->source, tasks)) {
+    if (!CanOptimize(fp->source.get(), tasks)) {
         return nullptr;
     }
 
diff --git a/fastboot/task_test.cpp b/fastboot/task_test.cpp
index 1e25b6f..9cde1a8 100644
--- a/fastboot/task_test.cpp
+++ b/fastboot/task_test.cpp
@@ -192,8 +192,7 @@
         GTEST_SKIP();
     }
 
-    LocalImageSource s;
-    fp->source = &s;
+    fp->source.reset(new LocalImageSource);
     fp->sparse_limit = std::numeric_limits<int64_t>::max();
 
     fastboot::MockFastbootDriver fb;
@@ -239,8 +238,7 @@
         GTEST_SKIP();
     }
 
-    LocalImageSource s;
-    fp->source = &s;
+    fp->source.reset(new LocalImageSource);
 
     fastboot::MockFastbootDriver fb;
     fp->fb = &fb;
@@ -260,7 +258,7 @@
                 ParseFastbootInfoLine(fp.get(), android::base::Tokenize(test.first, " "));
         auto flash_task = task->AsFlashTask();
         ASSERT_FALSE(flash_task == nullptr);
-        ASSERT_EQ(FlashTask::IsDynamicParitition(fp->source, flash_task), test.second);
+        ASSERT_EQ(FlashTask::IsDynamicParitition(fp->source.get(), flash_task), test.second);
     }
 }
 
@@ -269,8 +267,7 @@
         GTEST_SKIP();
     }
 
-    LocalImageSource s;
-    fp->source = &s;
+    fp->source.reset(new LocalImageSource);
     fp->sparse_limit = std::numeric_limits<int64_t>::max();
 
     fastboot::MockFastbootDriver fb;
@@ -301,7 +298,7 @@
     for (auto& test : patternmatchtest) {
         std::vector<std::unique_ptr<Task>> tasks = ParseFastbootInfo(fp.get(), test.first);
         tasks.erase(std::remove_if(tasks.begin(), tasks.end(), remove_if_callback), tasks.end());
-        ASSERT_EQ(OptimizedFlashSuperTask::CanOptimize(fp->source, tasks), test.second);
+        ASSERT_EQ(OptimizedFlashSuperTask::CanOptimize(fp->source.get(), tasks), test.second);
     }
 }
 
@@ -312,8 +309,7 @@
         GTEST_SKIP();
     }
 
-    LocalImageSource s;
-    fp->source = &s;
+    fp->source.reset(new LocalImageSource);
     fp->sparse_limit = std::numeric_limits<int64_t>::max();
 
     fastboot::MockFastbootDriver fb;
@@ -362,7 +358,7 @@
                     contains_optimized_task = true;
                 }
                 if (auto flash_task = task->AsFlashTask()) {
-                    if (FlashTask::IsDynamicParitition(fp->source, flash_task)) {
+                    if (FlashTask::IsDynamicParitition(fp->source.get(), flash_task)) {
                         return false;
                     }
                 }
diff --git a/fs_mgr/TEST_MAPPING b/fs_mgr/TEST_MAPPING
index 1694969..37b4988 100644
--- a/fs_mgr/TEST_MAPPING
+++ b/fs_mgr/TEST_MAPPING
@@ -16,7 +16,8 @@
       "name": "fiemap_writer_test"
     },
     {
-      "name": "fs_mgr_vendor_overlay_test"
+      "name": "fs_mgr_vendor_overlay_test",
+      "keywords": ["internal"]
     },
     {
       "name": "vts_libsnapshot_test"
diff --git a/fs_mgr/libfs_avb/tests/avb_util_test.cpp b/fs_mgr/libfs_avb/tests/avb_util_test.cpp
index 2e34920..ee83cda 100644
--- a/fs_mgr/libfs_avb/tests/avb_util_test.cpp
+++ b/fs_mgr/libfs_avb/tests/avb_util_test.cpp
@@ -655,10 +655,12 @@
             "      Partition Name:          boot\n"
             "      Rollback Index Location: 1\n"
             "      Public key (sha1):       cdbb77177f731920bbe0a0f94f84d9038ae0617d\n"
+            "      Flags:                   0\n"
             "    Chain Partition descriptor:\n"
             "      Partition Name:          system\n"
             "      Rollback Index Location: 2\n"
-            "      Public key (sha1):       2597c218aae470a130f61162feaae70afd97f011\n",
+            "      Public key (sha1):       2597c218aae470a130f61162feaae70afd97f011\n"
+            "      Flags:                   0\n",
             InfoImage("vbmeta.img"));
 
     android::base::unique_fd fd(open(vbmeta_path.value().c_str(), O_RDONLY | O_CLOEXEC));
@@ -876,10 +878,12 @@
             "      Partition Name:          boot\n"
             "      Rollback Index Location: 1\n"
             "      Public key (sha1):       cdbb77177f731920bbe0a0f94f84d9038ae0617d\n"
+            "      Flags:                   0\n"
             "    Chain Partition descriptor:\n"
             "      Partition Name:          vbmeta_system\n"
             "      Rollback Index Location: 2\n"
-            "      Public key (sha1):       2597c218aae470a130f61162feaae70afd97f011\n",
+            "      Public key (sha1):       2597c218aae470a130f61162feaae70afd97f011\n"
+            "      Flags:                   0\n",
             InfoImage("vbmeta.img"));
 
     bool fatal_error = false;
@@ -909,7 +913,8 @@
             "    Chain Partition descriptor:\n"
             "      Partition Name:          system\n"
             "      Rollback Index Location: 3\n"
-            "      Public key (sha1):       2597c218aae470a130f61162feaae70afd97f011\n",
+            "      Public key (sha1):       2597c218aae470a130f61162feaae70afd97f011\n"
+            "      Flags:                   0\n",
             InfoImage("vbmeta_system.img"));
 
     chained_descriptors = GetChainPartitionInfo(LoadVBMetaData("vbmeta_system.img"), &fatal_error);
diff --git a/fs_mgr/libfs_avb/tests/basic_test.cpp b/fs_mgr/libfs_avb/tests/basic_test.cpp
index 1c47c07..d49affb 100644
--- a/fs_mgr/libfs_avb/tests/basic_test.cpp
+++ b/fs_mgr/libfs_avb/tests/basic_test.cpp
@@ -268,10 +268,12 @@
             "      Partition Name:          boot\n"
             "      Rollback Index Location: 1\n"
             "      Public key (sha1):       cdbb77177f731920bbe0a0f94f84d9038ae0617d\n"
+            "      Flags:                   0\n"
             "    Chain Partition descriptor:\n"
             "      Partition Name:          system\n"
             "      Rollback Index Location: 2\n"
-            "      Public key (sha1):       2597c218aae470a130f61162feaae70afd97f011\n",
+            "      Public key (sha1):       2597c218aae470a130f61162feaae70afd97f011\n"
+            "      Flags:                   0\n",
             InfoImage("vbmeta.img"));
 }
 
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/inspect_cow.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/inspect_cow.cpp
index a6dee4f..83b5a12 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/inspect_cow.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/inspect_cow.cpp
@@ -22,6 +22,7 @@
 #include <string>
 #include <vector>
 
+#include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/unique_fd.h>
 #include <gflags/gflags.h>
@@ -38,11 +39,13 @@
 DEFINE_bool(verify_merge_sequence, false, "Verify merge order sequencing");
 DEFINE_bool(show_merge_sequence, false, "Show merge order sequence");
 DEFINE_bool(show_raw_ops, false, "Show raw ops directly from the underlying parser");
+DEFINE_string(extract_to, "", "Extract the COW contents to the given file");
 
 namespace android {
 namespace snapshot {
 
 using android::base::borrowed_fd;
+using android::base::unique_fd;
 
 void MyLogger(android::base::LogId, android::base::LogSeverity severity, const char*, const char*,
               unsigned int, const char* message) {
@@ -53,7 +56,7 @@
     }
 }
 
-static void ShowBad(CowReader& reader, const struct CowOperation* op) {
+static void ShowBad(CowReader& reader, const CowOperation* op) {
     size_t count;
     auto buffer = std::make_unique<uint8_t[]>(op->data_length);
 
@@ -104,12 +107,21 @@
 }
 
 static bool Inspect(const std::string& path) {
-    android::base::unique_fd fd(open(path.c_str(), O_RDONLY));
+    unique_fd fd(open(path.c_str(), O_RDONLY));
     if (fd < 0) {
         PLOG(ERROR) << "open failed: " << path;
         return false;
     }
 
+    unique_fd extract_to;
+    if (!FLAGS_extract_to.empty()) {
+        extract_to.reset(open(FLAGS_extract_to.c_str(), O_RDWR | O_CREAT | O_TRUNC, 0664));
+        if (extract_to < 0) {
+            PLOG(ERROR) << "could not open " << FLAGS_extract_to << " for writing";
+            return false;
+        }
+    }
+
     CowReader reader;
 
     auto start_time = std::chrono::steady_clock::now();
@@ -186,12 +198,23 @@
 
         if (!FLAGS_silent && FLAGS_show_ops) std::cout << *op << "\n";
 
-        if (FLAGS_decompress && op->type == kCowReplaceOp && op->compression != kCowCompressNone) {
+        if ((FLAGS_decompress || extract_to >= 0) && op->type == kCowReplaceOp) {
             if (reader.ReadData(op, buffer.data(), buffer.size()) < 0) {
                 std::cerr << "Failed to decompress for :" << *op << "\n";
                 success = false;
                 if (FLAGS_show_bad_data) ShowBad(reader, op);
             }
+            if (extract_to >= 0) {
+                off_t offset = uint64_t(op->new_block) * header.block_size;
+                if (!android::base::WriteFullyAtOffset(extract_to, buffer.data(), buffer.size(),
+                                                       offset)) {
+                    PLOG(ERROR) << "failed to write block " << op->new_block;
+                    return false;
+                }
+            }
+        } else if (extract_to >= 0 && !IsMetadataOp(*op) && op->type != kCowZeroOp) {
+            PLOG(ERROR) << "Cannot extract op yet: " << *op;
+            return false;
         }
 
         if (op->type == kCowSequenceOp && FLAGS_show_merge_sequence) {
diff --git a/fs_mgr/libsnapshot/snapuserd/Android.bp b/fs_mgr/libsnapshot/snapuserd/Android.bp
index 47a8685..1b0c563 100644
--- a/fs_mgr/libsnapshot/snapuserd/Android.bp
+++ b/fs_mgr/libsnapshot/snapuserd/Android.bp
@@ -293,3 +293,48 @@
         "vts",
     ],
 }
+
+cc_binary_host {
+    name: "snapuserd_extractor",
+    defaults: [
+        "fs_mgr_defaults",
+        "libsnapshot_cow_defaults",
+    ],
+    srcs: [
+        "testing/dm_user_harness.cpp",
+        "testing/harness.cpp",
+        "testing/host_harness.cpp",
+        "user-space-merge/extractor.cpp",
+        "snapuserd_extractor.cpp",
+    ],
+    cflags: [
+        "-D_FILE_OFFSET_BITS=64",
+        "-Wall",
+        "-Werror",
+    ],
+    shared_libs: [
+        "libbase",
+        "liblog",
+    ],
+    static_libs: [
+        "libbrotli",
+        "libcutils_sockets",
+        "libdm",
+        "libext2_uuid",
+        "libext4_utils",
+        "libfs_mgr_file_wait",
+        "libgflags",
+        "libsnapshot_cow",
+        "libsnapuserd",
+        "liburing",
+        "libz",
+    ],
+    include_dirs: [
+        "bionic/libc/kernel",
+        ".",
+    ],
+    header_libs: [
+        "libstorage_literals_headers",
+        "libfiemap_headers",
+    ],
+}
diff --git a/fs_mgr/libsnapshot/snapuserd/dm-snapshot-merge/snapuserd_worker.cpp b/fs_mgr/libsnapshot/snapuserd/dm-snapshot-merge/snapuserd_worker.cpp
index 559dcc7..571b352 100644
--- a/fs_mgr/libsnapshot/snapuserd/dm-snapshot-merge/snapuserd_worker.cpp
+++ b/fs_mgr/libsnapshot/snapuserd/dm-snapshot-merge/snapuserd_worker.cpp
@@ -103,7 +103,7 @@
     ssize_t rv = reader_->ReadData(cow_op, buffer, BLOCK_SZ);
     if (rv != BLOCK_SZ) {
         SNAP_LOG(ERROR) << "ProcessReplaceOp failed for block " << cow_op->new_block
-                        << ", return = " << rv;
+                        << ", return = " << rv << ", COW operation = " << *cow_op;
         return false;
     }
     return true;
diff --git a/fs_mgr/libsnapshot/snapuserd/snapuserd_extractor.cpp b/fs_mgr/libsnapshot/snapuserd/snapuserd_extractor.cpp
new file mode 100644
index 0000000..f46cd5b
--- /dev/null
+++ b/fs_mgr/libsnapshot/snapuserd/snapuserd_extractor.cpp
@@ -0,0 +1,68 @@
+// Copyright (C) 2023 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <fcntl.h>
+#include <linux/fs.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <iostream>
+#include <memory>
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/unique_fd.h>
+#include <gflags/gflags.h>
+#include "user-space-merge/extractor.h"
+
+using namespace std::string_literals;
+
+DEFINE_string(base, "", "Base device/image");
+DEFINE_string(cow, "", "COW device/image");
+DEFINE_string(out, "", "Output path");
+DEFINE_int32(num_sectors, 0, "Number of sectors to read");
+
+int main([[maybe_unused]] int argc, [[maybe_unused]] char** argv) {
+    android::base::InitLogging(argv);
+    gflags::ParseCommandLineFlags(&argc, &argv, true);
+
+    if (FLAGS_out.empty()) {
+        LOG(ERROR) << "Missing -out argument.";
+        return 1;
+    }
+    if (FLAGS_base.empty()) {
+        LOG(ERROR) << "Missing -base argument.";
+        return 1;
+    }
+    if (FLAGS_cow.empty()) {
+        LOG(ERROR) << "missing -out argument.";
+        return 1;
+    }
+    if (!FLAGS_num_sectors) {
+        LOG(ERROR) << "missing -num_sectors argument.";
+        return 1;
+    }
+
+    android::snapshot::Extractor extractor(FLAGS_base, FLAGS_cow);
+    if (!extractor.Init()) {
+        return 1;
+    }
+    if (!extractor.Extract(FLAGS_num_sectors, FLAGS_out)) {
+        return 1;
+    }
+    return 0;
+}
diff --git a/fs_mgr/libsnapshot/snapuserd/user-space-merge/extractor.cpp b/fs_mgr/libsnapshot/snapuserd/user-space-merge/extractor.cpp
new file mode 100644
index 0000000..c5718d5
--- /dev/null
+++ b/fs_mgr/libsnapshot/snapuserd/user-space-merge/extractor.cpp
@@ -0,0 +1,90 @@
+// Copyright (C) 2023 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "extractor.h"
+
+#include <fcntl.h>
+#include <linux/fs.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <iostream>
+#include <memory>
+
+#include <android-base/file.h>
+#include <android-base/properties.h>
+#include <android-base/unique_fd.h>
+
+using android::base::unique_fd;
+using namespace std::string_literals;
+
+namespace android {
+namespace snapshot {
+
+Extractor::Extractor(const std::string& base_path, const std::string& cow_path)
+    : base_path_(base_path), cow_path_(cow_path), control_name_("test") {}
+
+bool Extractor::Init() {
+    auto opener = factory_.CreateTestOpener(control_name_);
+    handler_ = std::make_shared<SnapshotHandler>(control_name_, cow_path_, base_path_, base_path_,
+                                                 opener, 1, false, false);
+    if (!handler_->InitCowDevice()) {
+        return false;
+    }
+    if (!handler_->InitializeWorkers()) {
+        return false;
+    }
+
+    read_worker_ = std::make_unique<ReadWorker>(cow_path_, base_path_, control_name_, base_path_,
+                                                handler_->GetSharedPtr(), opener);
+    if (!read_worker_->Init()) {
+        return false;
+    }
+    block_server_ = static_cast<TestBlockServer*>(read_worker_->block_server());
+
+    handler_thread_ = std::async(std::launch::async, &SnapshotHandler::Start, handler_.get());
+    return true;
+}
+
+Extractor::~Extractor() {
+    factory_.DeleteQueue(control_name_);
+}
+
+bool Extractor::Extract(off_t num_sectors, const std::string& out_path) {
+    unique_fd out_fd(open(out_path.c_str(), O_RDWR | O_CLOEXEC | O_TRUNC | O_CREAT, 0664));
+    if (out_fd < 0) {
+        PLOG(ERROR) << "Could not open for writing: " << out_path;
+        return false;
+    }
+
+    for (off_t i = 0; i < num_sectors; i++) {
+        if (!read_worker_->RequestSectors(i, 512)) {
+            LOG(ERROR) << "Read sector " << i << " failed.";
+            return false;
+        }
+        std::string result = std::move(block_server_->sent_io());
+        off_t offset = i * 512;
+        if (!android::base::WriteFullyAtOffset(out_fd, result.data(), result.size(), offset)) {
+            PLOG(ERROR) << "write failed";
+            return false;
+        }
+    }
+    return true;
+}
+
+}  // namespace snapshot
+}  // namespace android
diff --git a/fs_mgr/libsnapshot/snapuserd/user-space-merge/extractor.h b/fs_mgr/libsnapshot/snapuserd/user-space-merge/extractor.h
new file mode 100644
index 0000000..65285b1
--- /dev/null
+++ b/fs_mgr/libsnapshot/snapuserd/user-space-merge/extractor.h
@@ -0,0 +1,51 @@
+// Copyright (C) 2023 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <string>
+#include <thread>
+
+#include <android-base/unique_fd.h>
+#include "merge_worker.h"
+#include "read_worker.h"
+#include "snapuserd_core.h"
+#include "testing/host_harness.h"
+
+namespace android {
+namespace snapshot {
+
+class Extractor final {
+  public:
+    Extractor(const std::string& base_path, const std::string& cow_path);
+    ~Extractor();
+
+    bool Init();
+    bool Extract(off_t num_sectors, const std::string& out_path);
+
+  private:
+    std::string base_path_;
+    std::string cow_path_;
+
+    TestBlockServerFactory factory_;
+    HostTestHarness harness_;
+    std::string control_name_;
+    std::shared_ptr<SnapshotHandler> handler_;
+    std::unique_ptr<ReadWorker> read_worker_;
+    std::future<bool> handler_thread_;
+    TestBlockServer* block_server_ = nullptr;
+};
+
+}  // namespace snapshot
+}  // namespace android
diff --git a/fs_mgr/libsnapshot/snapuserd/user-space-merge/read_worker.cpp b/fs_mgr/libsnapshot/snapuserd/user-space-merge/read_worker.cpp
index b9ecfa5..5cb13e8 100644
--- a/fs_mgr/libsnapshot/snapuserd/user-space-merge/read_worker.cpp
+++ b/fs_mgr/libsnapshot/snapuserd/user-space-merge/read_worker.cpp
@@ -283,7 +283,8 @@
                 // We found the sector in mapping. Check the type of COW OP and
                 // process it.
                 if (!ProcessCowOp(it->second, buffer)) {
-                    SNAP_LOG(ERROR) << "ProcessCowOp failed";
+                    SNAP_LOG(ERROR)
+                            << "ProcessCowOp failed, sector = " << sector << ", size = " << sz;
                     return false;
                 }
 
diff --git a/fs_mgr/libsnapshot/tools/Android.bp b/fs_mgr/libsnapshot/tools/Android.bp
index cfa0cef..0f08286 100644
--- a/fs_mgr/libsnapshot/tools/Android.bp
+++ b/fs_mgr/libsnapshot/tools/Android.bp
@@ -20,3 +20,26 @@
 
     cflags: ["-Werror"],
 }
+
+
+cc_binary {
+    name: "basic_v2_cow_writer",
+    host_supported: true,
+    defaults: [
+        "fs_mgr_defaults",
+        "libsnapshot_cow_defaults",
+    ],
+
+    srcs: ["basic_v2_cow_writer.cpp"],
+
+    static_libs: [
+        "libsnapshot_cow",
+    ],
+
+    shared_libs: [
+        "libbase",
+        "liblog",
+    ],
+
+    cflags: ["-Werror"],
+}
diff --git a/fs_mgr/libsnapshot/tools/basic_v2_cow_writer.cpp b/fs_mgr/libsnapshot/tools/basic_v2_cow_writer.cpp
new file mode 100644
index 0000000..72fb0f5
--- /dev/null
+++ b/fs_mgr/libsnapshot/tools/basic_v2_cow_writer.cpp
@@ -0,0 +1,63 @@
+//
+// Copyright (C) 2023 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <libsnapshot/cow_compress.h>
+#include <libsnapshot/cow_format.h>
+#include <libsnapshot/cow_writer.h>
+#include <filesystem>
+
+#include "android-base/unique_fd.h"
+
+using namespace android::snapshot;
+
+// This writes a simple cow v2 file in the current directory. This file will serve as testdata for
+// ensuring our v3 cow reader will be able to read a cow file created by the v2 writer.
+//
+// WARNING: We should not be overriding this test file, as it will serve as historic marker for what
+// a device with old writer_v2 will write as a cow.
+void write_cow_v2() {
+    CowOptions options;
+    options.cluster_ops = 5;
+    options.num_merge_ops = 1;
+    std::string data = "This is some data, believe it";
+    data.resize(options.block_size, '\0');
+
+    char cwd_buffer[1024];
+    size_t cwd_buffer_size = sizeof(cwd_buffer);
+
+    // Get the current working directory path.
+    char* err = getcwd(cwd_buffer, cwd_buffer_size);
+    if (!err) {
+        LOG(ERROR) << "Couldn't get current directory";
+    }
+    android::base::unique_fd fd(open(strcat(cwd_buffer, "/cow_v2"), O_CREAT | O_RDWR, 0666));
+    if (fd.get() == -1) {
+        LOG(FATAL) << "couldn't open tmp_cow";
+    }
+    std::unique_ptr<ICowWriter> writer = CreateCowWriter(2, options, std::move(fd));
+    writer->AddCopy(0, 5);
+    writer->AddRawBlocks(2, data.data(), data.size());
+    writer->AddLabel(1);
+    writer->AddXorBlocks(50, data.data(), data.size(), 24, 10);
+    writer->AddZeroBlocks(5, 10);
+    writer->AddLabel(2);
+    writer->Finalize();
+}
+
+int main() {
+    write_cow_v2();
+}
diff --git a/fs_mgr/libsnapshot/tools/cow_benchmark.cpp b/fs_mgr/libsnapshot/tools/cow_benchmark.cpp
index da2b879..4d5e346 100644
--- a/fs_mgr/libsnapshot/tools/cow_benchmark.cpp
+++ b/fs_mgr/libsnapshot/tools/cow_benchmark.cpp
@@ -1,4 +1,18 @@
-
+//
+// Copyright (C) 2023 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
 #include <memory>
 
 #include <array>
diff --git a/fs_mgr/libsnapshot/tools/testdata/cow_v2 b/fs_mgr/libsnapshot/tools/testdata/cow_v2
new file mode 100644
index 0000000..9f37dfc
--- /dev/null
+++ b/fs_mgr/libsnapshot/tools/testdata/cow_v2
Binary files differ
diff --git a/init/capabilities.cpp b/init/capabilities.cpp
index ab6ff03..0e2cd2a 100644
--- a/init/capabilities.cpp
+++ b/init/capabilities.cpp
@@ -66,18 +66,12 @@
         CAP_MAP_ENTRY(WAKE_ALARM),
         CAP_MAP_ENTRY(BLOCK_SUSPEND),
         CAP_MAP_ENTRY(AUDIT_READ),
-#if defined(__BIONIC__)
         CAP_MAP_ENTRY(PERFMON),
         CAP_MAP_ENTRY(BPF),
         CAP_MAP_ENTRY(CHECKPOINT_RESTORE),
-#endif
 };
 
-#if defined(__BIONIC__)
 static_assert(CAP_LAST_CAP == CAP_CHECKPOINT_RESTORE, "CAP_LAST_CAP is not CAP_CHECKPOINT_RESTORE");
-#else
-static_assert(CAP_LAST_CAP == CAP_AUDIT_READ, "CAP_LAST_CAP is not CAP_AUDIT_READ");
-#endif
 
 static bool ComputeCapAmbientSupported() {
 #if defined(__ANDROID__)
diff --git a/init/capabilities.h b/init/capabilities.h
index 891e0ac..fc80c98 100644
--- a/init/capabilities.h
+++ b/init/capabilities.h
@@ -21,17 +21,6 @@
 #include <string>
 #include <type_traits>
 
-#if !defined(__ANDROID__)
-#ifndef CAP_BLOCK_SUSPEND
-#define CAP_BLOCK_SUSPEND 36
-#endif
-#ifndef CAP_AUDIT_READ
-#define CAP_AUDIT_READ 37
-#endif
-#undef CAP_LAST_CAP
-#define CAP_LAST_CAP CAP_AUDIT_READ
-#endif
-
 namespace android {
 namespace init {
 
diff --git a/libutils/include/utils/String16.h b/libutils/include/utils/String16.h
index 1fa3723..c713576 100644
--- a/libutils/include/utils/String16.h
+++ b/libutils/include/utils/String16.h
@@ -59,7 +59,6 @@
                                 ~String16();
 
     inline  const char16_t*     c_str() const;
-    inline  const char16_t*     string() const;
 
             size_t              size() const;
     inline  bool                empty() const;
@@ -188,6 +187,14 @@
 
     template <size_t N>
     explicit constexpr String16(const StaticData<N>& s) : mString(s.data) {}
+
+// These symbols are for potential backward compatibility with prebuilts. To be removed.
+#ifdef ENABLE_STRING16_OBSOLETE_METHODS
+public:
+#else
+private:
+#endif
+    inline  const char16_t*     string() const;
 };
 
 // String16 can be trivially moved using memcpy() because moving does not
diff --git a/libutils/include/utils/String8.h b/libutils/include/utils/String8.h
index 0b92f5b..6d25072 100644
--- a/libutils/include/utils/String8.h
+++ b/libutils/include/utils/String8.h
@@ -65,7 +65,6 @@
     static String8              formatV(const char* fmt, va_list args);
 
     inline  const char*         c_str() const;
-    inline  const char*         string() const;
 
     inline  size_t              size() const;
     inline  size_t              bytes() const;
@@ -155,6 +154,7 @@
 #else
 private:
 #endif
+    inline  const char*         string() const;
     inline  bool                isEmpty() const;
 };
 
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 8eec16c..fb64736 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -1056,6 +1056,9 @@
     write /proc/sys/vm/dirty_expire_centisecs 200
     write /proc/sys/vm/dirty_background_ratio  5
 
+on boot && property:suspend.disable_sync_on_suspend=true
+    write /sys/power/sync_on_suspend 0
+
 on boot
     # basic network init
     ifup lo
diff --git a/trusty/utils/coverage-controller/controller.cpp b/trusty/utils/coverage-controller/controller.cpp
index 0047046..381a452 100644
--- a/trusty/utils/coverage-controller/controller.cpp
+++ b/trusty/utils/coverage-controller/controller.cpp
@@ -54,7 +54,7 @@
             if (complete_cnt != counters[index] && start_cnt == complete_cnt) {
                 WRITE_ONCE(control->cntrl_flags, FLAG_NONE);
                 std::string filename;
-                filename = android::base::StringPrintf("/%s.%lu.profraw",
+                filename = android::base::StringPrintf("/%s.%" PRIu64 ".profraw",
                                                     uuid_list_[index].c_str(),
                                                     counters[index]);
                 filename.insert(0, output_dir);