diff --git a/adb/Android.bp b/adb/Android.bp
index 57872b0..9ef82bf 100644
--- a/adb/Android.bp
+++ b/adb/Android.bp
@@ -629,6 +629,7 @@
         "libselinux",
     ],
     test_suites: ["device-tests"],
+    require_root: true,
 }
 
 python_test_host {
diff --git a/debuggerd/debuggerd_test.cpp b/debuggerd/debuggerd_test.cpp
index c617c6c..c9a193c 100644
--- a/debuggerd/debuggerd_test.cpp
+++ b/debuggerd/debuggerd_test.cpp
@@ -195,9 +195,7 @@
 void CrasherTest::FinishIntercept(int* result) {
   InterceptResponse response;
 
-  // Timeout for tombstoned intercept is 10 seconds.
-  ssize_t rc =
-      TIMEOUT(20, TEMP_FAILURE_RETRY(read(intercept_fd.get(), &response, sizeof(response))));
+  ssize_t rc = TIMEOUT(30, read(intercept_fd.get(), &response, sizeof(response)));
   if (rc == -1) {
     FAIL() << "failed to read response from tombstoned: " << strerror(errno);
   } else if (rc == 0) {
@@ -244,7 +242,7 @@
 
 void CrasherTest::AssertDeath(int signo) {
   int status;
-  pid_t pid = TIMEOUT(10, TEMP_FAILURE_RETRY(waitpid(crasher_pid, &status, 0)));
+  pid_t pid = TIMEOUT(30, waitpid(crasher_pid, &status, 0));
   if (pid != crasher_pid) {
     printf("failed to wait for crasher (expected pid %d, return value %d): %s\n", crasher_pid, pid,
            strerror(errno));
diff --git a/fastboot/Android.bp b/fastboot/Android.bp
index 546bce2..f452a64 100644
--- a/fastboot/Android.bp
+++ b/fastboot/Android.bp
@@ -189,7 +189,11 @@
     // will violate ODR.
     shared_libs: [],
 
-    header_libs: ["bootimg_headers"],
+    header_libs: [
+        "avb_headers",
+        "bootimg_headers",
+    ],
+
     static_libs: [
         "libziparchive",
         "libsparse",
diff --git a/fastboot/fastboot.cpp b/fastboot/fastboot.cpp
index a7fc628..2fe3b1a 100644
--- a/fastboot/fastboot.cpp
+++ b/fastboot/fastboot.cpp
@@ -51,6 +51,7 @@
 #include <utility>
 #include <vector>
 
+#include <android-base/endian.h>
 #include <android-base/file.h>
 #include <android-base/macros.h>
 #include <android-base/parseint.h>
@@ -59,6 +60,7 @@
 #include <android-base/strings.h>
 #include <android-base/unique_fd.h>
 #include <build/version.h>
+#include <libavb/libavb.h>
 #include <liblp/liblp.h>
 #include <platform_tools_version.h>
 #include <sparse/sparse.h>
@@ -919,33 +921,50 @@
     return load_buf_fd(fd.release(), buf);
 }
 
-static void rewrite_vbmeta_buffer(struct fastboot_buffer* buf) {
+static void rewrite_vbmeta_buffer(struct fastboot_buffer* buf, bool vbmeta_in_boot) {
     // Buffer needs to be at least the size of the VBMeta struct which
     // is 256 bytes.
     if (buf->sz < 256) {
         return;
     }
 
-    int fd = make_temporary_fd("vbmeta rewriting");
-
     std::string data;
     if (!android::base::ReadFdToString(buf->fd, &data)) {
         die("Failed reading from vbmeta");
     }
 
+    uint64_t vbmeta_offset = 0;
+    if (vbmeta_in_boot) {
+        // Tries to locate top-level vbmeta from boot.img footer.
+        uint64_t footer_offset = buf->sz - AVB_FOOTER_SIZE;
+        if (0 != data.compare(footer_offset, AVB_FOOTER_MAGIC_LEN, AVB_FOOTER_MAGIC)) {
+            die("Failed to find AVB_FOOTER at offset: %" PRId64, footer_offset);
+        }
+        const AvbFooter* footer = reinterpret_cast<const AvbFooter*>(data.c_str() + footer_offset);
+        vbmeta_offset = be64toh(footer->vbmeta_offset);
+    }
+    // Ensures there is AVB_MAGIC at vbmeta_offset.
+    if (0 != data.compare(vbmeta_offset, AVB_MAGIC_LEN, AVB_MAGIC)) {
+        die("Failed to find AVB_MAGIC at offset: %" PRId64, vbmeta_offset);
+    }
+
+    fprintf(stderr, "Rewriting vbmeta struct at offset: %" PRId64 "\n", vbmeta_offset);
+
     // There's a 32-bit big endian |flags| field at offset 120 where
     // bit 0 corresponds to disable-verity and bit 1 corresponds to
     // disable-verification.
     //
     // See external/avb/libavb/avb_vbmeta_image.h for the layout of
     // the VBMeta struct.
+    uint64_t flags_offset = 123 + vbmeta_offset;
     if (g_disable_verity) {
-        data[123] |= 0x01;
+        data[flags_offset] |= 0x01;
     }
     if (g_disable_verification) {
-        data[123] |= 0x02;
+        data[flags_offset] |= 0x02;
     }
 
+    int fd = make_temporary_fd("vbmeta rewriting");
     if (!android::base::WriteStringToFd(data, fd)) {
         die("Failed writing to modified vbmeta");
     }
@@ -954,14 +973,25 @@
     lseek(fd, 0, SEEK_SET);
 }
 
+static bool has_vbmeta_partition() {
+    std::string partition_type;
+    return fb->GetVar("partition-type:vbmeta", &partition_type) == fastboot::SUCCESS ||
+           fb->GetVar("partition-type:vbmeta_a", &partition_type) == fastboot::SUCCESS ||
+           fb->GetVar("partition-type:vbmeta_b", &partition_type) == fastboot::SUCCESS;
+}
+
 static void flash_buf(const std::string& partition, struct fastboot_buffer *buf)
 {
     sparse_file** s;
 
     // Rewrite vbmeta if that's what we're flashing and modification has been requested.
-    if ((g_disable_verity || g_disable_verification) &&
-        (partition == "vbmeta" || partition == "vbmeta_a" || partition == "vbmeta_b")) {
-        rewrite_vbmeta_buffer(buf);
+    if (g_disable_verity || g_disable_verification) {
+        if (partition == "vbmeta" || partition == "vbmeta_a" || partition == "vbmeta_b") {
+            rewrite_vbmeta_buffer(buf, false /* vbmeta_in_boot */);
+        } else if (!has_vbmeta_partition() &&
+                   (partition == "boot" || partition == "boot_a" || partition == "boot_b")) {
+            rewrite_vbmeta_buffer(buf, true /* vbmeta_in_boot */ );
+        }
     }
 
     switch (buf->type) {
diff --git a/fs_mgr/fs_mgr_fstab.cpp b/fs_mgr/fs_mgr_fstab.cpp
index 4dbacd7..e50f7c3 100644
--- a/fs_mgr/fs_mgr_fstab.cpp
+++ b/fs_mgr/fs_mgr_fstab.cpp
@@ -36,6 +36,7 @@
 
 #include "fs_mgr_priv.h"
 
+using android::base::EndsWith;
 using android::base::ParseByteCount;
 using android::base::ParseInt;
 using android::base::ReadFileToString;
@@ -598,7 +599,7 @@
     return boot_devices;
 }
 
-FstabEntry BuildGsiUserdataFstabEntry() {
+FstabEntry BuildDsuUserdataFstabEntry() {
     constexpr uint32_t kFlags = MS_NOATIME | MS_NOSUID | MS_NODEV;
 
     FstabEntry userdata = {
@@ -627,7 +628,12 @@
     return false;
 }
 
-void TransformFstabForGsi(Fstab* fstab) {
+}  // namespace
+
+void TransformFstabForDsu(Fstab* fstab, const std::vector<std::string>& dsu_partitions) {
+    static constexpr char kGsiKeys[] =
+            "/avb/q-gsi.avbpubkey:/avb/r-gsi.avbpubkey:/avb/s-gsi.avbpubkey";
+    // Convert userdata
     // Inherit fstab properties for userdata.
     FstabEntry userdata;
     if (FstabEntry* entry = GetEntryForMountPoint(fstab, "/data")) {
@@ -639,19 +645,75 @@
             userdata.key_dir += "/gsi";
         }
     } else {
-        userdata = BuildGsiUserdataFstabEntry();
-    }
-
-    if (EraseFstabEntry(fstab, "/system")) {
-        fstab->emplace_back(BuildGsiSystemFstabEntry());
+        userdata = BuildDsuUserdataFstabEntry();
     }
 
     if (EraseFstabEntry(fstab, "/data")) {
         fstab->emplace_back(userdata);
     }
-}
 
-}  // namespace
+    // Convert others
+    for (auto&& partition : dsu_partitions) {
+        if (!EndsWith(partition, gsi::kDsuPostfix)) {
+            continue;
+        }
+        // userdata has been handled
+        if (StartsWith(partition, "user")) {
+            continue;
+        }
+        // dsu_partition_name = corresponding_partition_name + kDsuPostfix
+        // e.g.
+        //    system_gsi for system
+        //    product_gsi for product
+        //    vendor_gsi for vendor
+        std::string lp_name = partition.substr(0, partition.length() - strlen(gsi::kDsuPostfix));
+        std::string mount_point = "/" + lp_name;
+        std::vector<FstabEntry*> entries = GetEntriesForMountPoint(fstab, mount_point);
+        if (entries.empty()) {
+            FstabEntry entry = {
+                    .blk_device = partition,
+                    .mount_point = mount_point,
+                    .fs_type = "ext4",
+                    .flags = MS_RDONLY,
+                    .fs_options = "barrier=1",
+                    .avb_keys = kGsiKeys,
+                    // .logical_partition_name is required to look up AVB Hashtree descriptors.
+                    .logical_partition_name = "system"};
+            entry.fs_mgr_flags.wait = true;
+            entry.fs_mgr_flags.logical = true;
+            entry.fs_mgr_flags.first_stage_mount = true;
+            // Use the system key which may be in the vbmeta or vbmeta_system
+            // TODO: b/141284191
+            entry.vbmeta_partition = "vbmeta";
+            fstab->emplace_back(entry);
+            entry.vbmeta_partition = "vbmeta_system";
+            fstab->emplace_back(entry);
+        } else {
+            // If the corresponding partition exists, transform all its Fstab
+            // by pointing .blk_device to the DSU partition.
+            for (auto&& entry : entries) {
+                entry->blk_device = partition;
+                if (entry->avb_keys.size() > 0) {
+                    entry->avb_keys += ":";
+                }
+                // If the DSU is signed by OEM, the original Fstab already has the information
+                // required by avb, otherwise the DSU is GSI and will need the avb_keys as listed
+                // below.
+                entry->avb_keys += kGsiKeys;
+            }
+            // Make sure the ext4 is included to support GSI.
+            auto partition_ext4 =
+                    std::find_if(fstab->begin(), fstab->end(), [&](const auto& entry) {
+                        return entry.mount_point == mount_point && entry.fs_type == "ext4";
+                    });
+            if (partition_ext4 == fstab->end()) {
+                auto new_entry = *GetEntryForMountPoint(fstab, mount_point);
+                new_entry.fs_type = "ext4";
+                fstab->emplace_back(new_entry);
+            }
+        }
+    }
+}
 
 bool ReadFstabFromFile(const std::string& path, Fstab* fstab) {
     auto fstab_file = std::unique_ptr<FILE, decltype(&fclose)>{fopen(path.c_str(), "re"), fclose};
@@ -667,7 +729,9 @@
         return false;
     }
     if (!is_proc_mounts && !access(android::gsi::kGsiBootedIndicatorFile, F_OK)) {
-        TransformFstabForGsi(fstab);
+        std::string lp_names;
+        ReadFileToString(gsi::kGsiLpNamesFile, &lp_names);
+        TransformFstabForDsu(fstab, Split(lp_names, ","));
     }
 
     SkipMountingPartitions(fstab);
@@ -779,6 +843,21 @@
     return nullptr;
 }
 
+std::vector<FstabEntry*> GetEntriesForMountPoint(Fstab* fstab, const std::string& path) {
+    std::vector<FstabEntry*> entries;
+    if (fstab == nullptr) {
+        return entries;
+    }
+
+    for (auto& entry : *fstab) {
+        if (entry.mount_point == path) {
+            entries.emplace_back(&entry);
+        }
+    }
+
+    return entries;
+}
+
 std::set<std::string> GetBootDevices() {
     // First check the kernel commandline, then try the device tree otherwise
     std::string dt_file_name = get_android_dt_dir() + "/boot_devices";
@@ -798,23 +877,6 @@
     return ExtraBootDevices(fstab);
 }
 
-FstabEntry BuildGsiSystemFstabEntry() {
-    // .logical_partition_name is required to look up AVB Hashtree descriptors.
-    FstabEntry system = {
-            .blk_device = "system_gsi",
-            .mount_point = "/system",
-            .fs_type = "ext4",
-            .flags = MS_RDONLY,
-            .fs_options = "barrier=1",
-            // could add more keys separated by ':'.
-            .avb_keys = "/avb/q-gsi.avbpubkey:/avb/r-gsi.avbpubkey:/avb/s-gsi.avbpubkey",
-            .logical_partition_name = "system"};
-    system.fs_mgr_flags.wait = true;
-    system.fs_mgr_flags.logical = true;
-    system.fs_mgr_flags.first_stage_mount = true;
-    return system;
-}
-
 std::string GetVerityDeviceName(const FstabEntry& entry) {
     std::string base_device;
     if (entry.mount_point == "/") {
diff --git a/fs_mgr/include_fstab/fstab/fstab.h b/fs_mgr/include_fstab/fstab/fstab.h
index c7193ab..d999ae1 100644
--- a/fs_mgr/include_fstab/fstab/fstab.h
+++ b/fs_mgr/include_fstab/fstab/fstab.h
@@ -101,9 +101,18 @@
 bool SkipMountingPartitions(Fstab* fstab);
 
 FstabEntry* GetEntryForMountPoint(Fstab* fstab, const std::string& path);
+// The Fstab can contain multiple entries for the same mount point with different configurations.
+std::vector<FstabEntry*> GetEntriesForMountPoint(Fstab* fstab, const std::string& path);
 
-// Helper method to build a GSI fstab entry for mounting /system.
-FstabEntry BuildGsiSystemFstabEntry();
+// This method builds DSU fstab entries and transfer the fstab.
+//
+// fstab points to the unmodified fstab.
+//
+// dsu_partitions contains partition names, e.g.
+//     dsu_partitions[0] = "system_gsi"
+//     dsu_partitions[1] = "userdata_gsi"
+//     dsu_partitions[2] = ...
+void TransformFstabForDsu(Fstab* fstab, const std::vector<std::string>& dsu_partitions);
 
 std::set<std::string> GetBootDevices();
 
diff --git a/fs_mgr/libdm/Android.bp b/fs_mgr/libdm/Android.bp
index 4cdea71..449a170 100644
--- a/fs_mgr/libdm/Android.bp
+++ b/fs_mgr/libdm/Android.bp
@@ -44,9 +44,24 @@
     },
 }
 
-cc_test {
-    name: "libdm_test",
-    defaults: ["fs_mgr_defaults"],
+filegroup {
+    name: "libdm_test_srcs",
+    srcs: [
+        "dm_test.cpp",
+        "loop_control_test.cpp",
+        "test_util.cpp",
+    ],
+}
+
+cc_defaults {
+    name: "libdm_defaults",
+    sanitize: {
+        misc_undefined: ["integer"],
+    },
+    cflags: [
+        "-Wall",
+        "-Werror",
+    ],
     static_libs: [
         "libdm",
         "libbase",
@@ -54,9 +69,10 @@
         "libfs_mgr",
         "liblog",
     ],
-    srcs: [
-        "dm_test.cpp",
-        "loop_control_test.cpp",
-        "test_util.cpp",
-    ]
+    srcs: [":libdm_test_srcs"],
+}
+
+cc_test {
+    name: "libdm_test",
+    defaults: ["libdm_defaults"],
 }
diff --git a/fs_mgr/libdm/vts_core/Android.bp b/fs_mgr/libdm/vts_core/Android.bp
new file mode 100644
index 0000000..2eceb28
--- /dev/null
+++ b/fs_mgr/libdm/vts_core/Android.bp
@@ -0,0 +1,23 @@
+//
+// Copyright (C) 2019 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.
+//
+
+cc_test {
+    name: "vts_libdm_test",
+    defaults: ["libdm_defaults"],
+    test_suites: ["vts-core"],
+    require_root: true,
+    test_min_api_level: 29,
+}
diff --git a/fs_mgr/liblp/Android.bp b/fs_mgr/liblp/Android.bp
index b2572f6..7fee83c 100644
--- a/fs_mgr/liblp/Android.bp
+++ b/fs_mgr/liblp/Android.bp
@@ -55,9 +55,26 @@
     export_include_dirs: ["include"],
 }
 
+filegroup {
+    name: "liblp_test_srcs",
+    srcs: [
+        "builder_test.cpp",
+        "device_test.cpp",
+        "io_test.cpp",
+        "test_partition_opener.cpp",
+        "utility_test.cpp",
+    ],
+}
+
 cc_defaults {
     name: "liblp_test_defaults",
-    defaults: ["fs_mgr_defaults"],
+    sanitize: {
+        misc_undefined: ["integer"],
+    },
+    cflags: [
+        "-Wall",
+        "-Werror",
+    ],
     cppflags: [
         "-Wno-unused-parameter",
     ],
@@ -71,23 +88,14 @@
         "libstorage_literals_headers",
     ],
     stl: "libc++_static",
-    srcs: [
-        "builder_test.cpp",
-        "device_test.cpp",
-        "io_test.cpp",
-        "test_partition_opener.cpp",
-        "utility_test.cpp",
-    ],
+    srcs: [":liblp_test_srcs"],
 }
 
 cc_test {
     name: "liblp_test",
     defaults: ["liblp_test_defaults"],
     test_config: "liblp_test.xml",
-    test_suites: [
-        "device-tests",
-        "vts-core",
-    ],
+    test_suites: ["device-tests"],
 }
 
 cc_test {
diff --git a/fs_mgr/liblp/vts_core/Android.bp b/fs_mgr/liblp/vts_core/Android.bp
new file mode 100644
index 0000000..7af0b9e
--- /dev/null
+++ b/fs_mgr/liblp/vts_core/Android.bp
@@ -0,0 +1,22 @@
+//
+// Copyright (C) 2019 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.
+//
+
+cc_test {
+    name: "vts_core_liblp_test",
+    defaults: ["liblp_test_defaults"],
+    test_suites: ["vts-core"],
+    test_min_api_level: 29,
+}
diff --git a/fs_mgr/libsnapshot/Android.bp b/fs_mgr/libsnapshot/Android.bp
index bb941dd..a012099 100644
--- a/fs_mgr/libsnapshot/Android.bp
+++ b/fs_mgr/libsnapshot/Android.bp
@@ -114,3 +114,29 @@
         "libstorage_literals_headers",
     ],
 }
+
+cc_binary {
+    name: "snapshotctl",
+    srcs: [
+        "snapshotctl.cpp",
+    ],
+    static_libs: [
+        "libdm",
+        "libext2_uuid",
+        "libfiemap_binder",
+        "libfstab",
+        "libsnapshot",
+    ],
+    shared_libs: [
+        "libbase",
+        "libbinder",
+        "libext4_utils",
+        "libfs_mgr",
+        "libutils",
+        "liblog",
+        "liblp",
+    ],
+    init_rc: [
+        "snapshotctl.rc",
+    ],
+}
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
index aeeb4aa..0dd275a 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
@@ -19,6 +19,7 @@
 #include <chrono>
 #include <map>
 #include <memory>
+#include <ostream>
 #include <string>
 #include <string_view>
 #include <vector>
@@ -84,6 +85,7 @@
     // operation via fastboot. This state can only be returned by WaitForMerge.
     Cancelled
 };
+std::ostream& operator<<(std::ostream& os, UpdateState state);
 
 class SnapshotManager final {
     using CreateLogicalPartitionParams = android::fs_mgr::CreateLogicalPartitionParams;
@@ -125,8 +127,9 @@
     // will fail if GetUpdateState() != None.
     bool BeginUpdate();
 
-    // Cancel an update; any snapshots will be deleted. This will fail if the
-    // state != Initiated or None.
+    // Cancel an update; any snapshots will be deleted. This is allowed if the
+    // state == Initiated, None, or Unverified (before rebooting to the new
+    // slot).
     bool CancelUpdate();
 
     // Mark snapshot writes as having completed. After this, new snapshots cannot
@@ -189,6 +192,9 @@
     // call to CreateLogicalPartitions when snapshots are present.
     bool CreateLogicalAndSnapshotPartitions(const std::string& super_device);
 
+    // Dump debug information.
+    bool Dump(std::ostream& os);
+
   private:
     FRIEND_TEST(SnapshotTest, CleanFirstStageMount);
     FRIEND_TEST(SnapshotTest, CreateSnapshot);
@@ -393,6 +399,13 @@
     // The reverse of MapPartitionWithSnapshot.
     bool UnmapPartitionWithSnapshot(LockedFile* lock, const std::string& target_partition_name);
 
+    // If there isn't a previous update, return true. |needs_merge| is set to false.
+    // If there is a previous update but the device has not boot into it, tries to cancel the
+    //   update and delete any snapshots. Return true if successful. |needs_merge| is set to false.
+    // If there is a previous update and the device has boot into it, do nothing and return true.
+    //   |needs_merge| is set to true.
+    bool TryCancelUpdate(bool* needs_merge);
+
     std::string gsid_dir_;
     std::string metadata_dir_;
     std::unique_ptr<IDeviceInfo> device_;
diff --git a/fs_mgr/libsnapshot/snapshot.cpp b/fs_mgr/libsnapshot/snapshot.cpp
index b5b3af3..9d0272b 100644
--- a/fs_mgr/libsnapshot/snapshot.cpp
+++ b/fs_mgr/libsnapshot/snapshot.cpp
@@ -131,6 +131,16 @@
 }
 
 bool SnapshotManager::BeginUpdate() {
+    bool needs_merge = false;
+    if (!TryCancelUpdate(&needs_merge)) {
+        return false;
+    }
+    if (needs_merge) {
+        LOG(INFO) << "Wait for merge (if any) before beginning a new update.";
+        auto state = ProcessUpdateState();
+        LOG(INFO) << "Merged with state = " << state;
+    }
+
     auto file = LockExclusive();
     if (!file) return false;
 
@@ -143,6 +153,19 @@
 }
 
 bool SnapshotManager::CancelUpdate() {
+    bool needs_merge = false;
+    if (!TryCancelUpdate(&needs_merge)) {
+        return false;
+    }
+    if (needs_merge) {
+        LOG(ERROR) << "Cannot cancel update after it has completed or started merging";
+    }
+    return !needs_merge;
+}
+
+bool SnapshotManager::TryCancelUpdate(bool* needs_merge) {
+    *needs_merge = false;
+
     auto file = LockExclusive();
     if (!file) return false;
 
@@ -167,8 +190,8 @@
             return RemoveAllUpdateState(file.get());
         }
     }
-    LOG(ERROR) << "Cannot cancel update after it has completed or started merging";
-    return false;
+    *needs_merge = true;
+    return true;
 }
 
 bool SnapshotManager::RemoveAllUpdateState(LockedFile* lock) {
@@ -1459,7 +1482,7 @@
         PLOG(ERROR) << "Open failed: " << file;
         return nullptr;
     }
-    if (flock(fd, lock_flags) < 0) {
+    if (lock_flags != 0 && flock(fd, lock_flags) < 0) {
         PLOG(ERROR) << "Acquire flock failed: " << file;
         return nullptr;
     }
@@ -1526,34 +1549,33 @@
     }
 }
 
-bool SnapshotManager::WriteUpdateState(LockedFile* file, UpdateState state) {
-    std::string contents;
+std::ostream& operator<<(std::ostream& os, UpdateState state) {
     switch (state) {
         case UpdateState::None:
-            contents = "none";
-            break;
+            return os << "none";
         case UpdateState::Initiated:
-            contents = "initiated";
-            break;
+            return os << "initiated";
         case UpdateState::Unverified:
-            contents = "unverified";
-            break;
+            return os << "unverified";
         case UpdateState::Merging:
-            contents = "merging";
-            break;
+            return os << "merging";
         case UpdateState::MergeCompleted:
-            contents = "merge-completed";
-            break;
+            return os << "merge-completed";
         case UpdateState::MergeNeedsReboot:
-            contents = "merge-needs-reboot";
-            break;
+            return os << "merge-needs-reboot";
         case UpdateState::MergeFailed:
-            contents = "merge-failed";
-            break;
+            return os << "merge-failed";
         default:
             LOG(ERROR) << "Unknown update state";
-            return false;
+            return os;
     }
+}
+
+bool SnapshotManager::WriteUpdateState(LockedFile* file, UpdateState state) {
+    std::stringstream ss;
+    ss << state;
+    std::string contents = ss.str();
+    if (contents.empty()) return false;
 
     if (!Truncate(file)) return false;
     if (!android::base::WriteStringToFd(contents, file->fd())) {
@@ -1940,5 +1962,47 @@
     return UnmapPartitionWithSnapshot(lock.get(), target_partition_name);
 }
 
+bool SnapshotManager::Dump(std::ostream& os) {
+    // Don't actually lock. Dump() is for debugging purposes only, so it is okay
+    // if it is racy.
+    auto file = OpenStateFile(O_RDONLY, 0);
+    if (!file) return false;
+
+    std::stringstream ss;
+
+    ss << "Update state: " << ReadUpdateState(file.get()) << std::endl;
+
+    auto boot_file = GetSnapshotBootIndicatorPath();
+    std::string boot_indicator;
+    if (android::base::ReadFileToString(boot_file, &boot_indicator)) {
+        ss << "Boot indicator: old slot = " << boot_indicator << std::endl;
+    }
+
+    bool ok = true;
+    std::vector<std::string> snapshots;
+    if (!ListSnapshots(file.get(), &snapshots)) {
+        LOG(ERROR) << "Could not list snapshots";
+        snapshots.clear();
+        ok = false;
+    }
+    for (const auto& name : snapshots) {
+        ss << "Snapshot: " << name << std::endl;
+        SnapshotStatus status;
+        if (!ReadSnapshotStatus(file.get(), name, &status)) {
+            ok = false;
+            continue;
+        }
+        ss << "    state: " << to_string(status.state) << std::endl;
+        ss << "    device size (bytes): " << status.device_size << std::endl;
+        ss << "    snapshot size (bytes): " << status.snapshot_size << std::endl;
+        ss << "    cow partition size (bytes): " << status.cow_partition_size << std::endl;
+        ss << "    cow file size (bytes): " << status.cow_file_size << std::endl;
+        ss << "    allocated sectors: " << status.sectors_allocated << std::endl;
+        ss << "    metadata sectors: " << status.metadata_sectors << std::endl;
+    }
+    os << ss.rdbuf();
+    return ok;
+}
+
 }  // namespace snapshot
 }  // namespace android
diff --git a/fs_mgr/libsnapshot/snapshot_test.cpp b/fs_mgr/libsnapshot/snapshot_test.cpp
index 36982a9..bc764fd 100644
--- a/fs_mgr/libsnapshot/snapshot_test.cpp
+++ b/fs_mgr/libsnapshot/snapshot_test.cpp
@@ -761,8 +761,7 @@
 // Also test UnmapUpdateSnapshot unmaps everything.
 // Also test first stage mount and merge after this.
 TEST_F(SnapshotUpdateTest, FullUpdateFlow) {
-    // OTA client calls CancelUpdate then BeginUpdate before doing anything.
-    ASSERT_TRUE(sm->CancelUpdate());
+    // OTA client calls BeginUpdate before doing anything.
     ASSERT_TRUE(sm->BeginUpdate());
 
     // OTA client blindly unmaps all partitions that are possibly mapped.
diff --git a/fs_mgr/libsnapshot/snapshotctl.cpp b/fs_mgr/libsnapshot/snapshotctl.cpp
new file mode 100644
index 0000000..d65320c
--- /dev/null
+++ b/fs_mgr/libsnapshot/snapshotctl.cpp
@@ -0,0 +1,115 @@
+//
+// Copyright (C) 2019 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 <sysexits.h>
+
+#include <chrono>
+#include <iostream>
+#include <map>
+
+#include <android-base/logging.h>
+#include <libsnapshot/snapshot.h>
+
+using namespace std::string_literals;
+
+int Usage() {
+    std::cerr << "snapshotctl: Control snapshots.\n"
+                 "Usage: snapshotctl [action] [flags]\n"
+                 "Actions:\n"
+                 "  dump\n"
+                 "    Print snapshot states.\n"
+                 "  merge [--logcat]\n"
+                 "    Initialize merge and wait for it to be completed.\n"
+                 "    If --logcat is specified, log to logcat. Otherwise, log to stdout.\n";
+    return EX_USAGE;
+}
+
+namespace android {
+namespace snapshot {
+
+bool DumpCmdHandler(int /*argc*/, char** argv) {
+    android::base::InitLogging(argv, &android::base::StderrLogger);
+    return SnapshotManager::New()->Dump(std::cout);
+}
+
+bool MergeCmdHandler(int argc, char** argv) {
+    auto begin = std::chrono::steady_clock::now();
+
+    bool log_to_logcat = false;
+    for (int i = 2; i < argc; ++i) {
+        if (argv[i] == "--logcat"s) {
+            log_to_logcat = true;
+        }
+    }
+    if (log_to_logcat) {
+        android::base::InitLogging(argv);
+    } else {
+        android::base::InitLogging(argv, &android::base::StdioLogger);
+    }
+
+    auto sm = SnapshotManager::New();
+
+    auto state = sm->GetUpdateState();
+    if (state == UpdateState::None) {
+        LOG(INFO) << "Can't find any snapshot to merge.";
+        return true;
+    }
+    if (state == UpdateState::Unverified) {
+        if (!sm->InitiateMerge()) {
+            LOG(ERROR) << "Failed to initiate merge.";
+            return false;
+        }
+    }
+
+    // All other states can be handled by ProcessUpdateState.
+    LOG(INFO) << "Waiting for any merge to complete. This can take up to 1 minute.";
+    state = SnapshotManager::New()->ProcessUpdateState();
+
+    if (state == UpdateState::MergeCompleted) {
+        auto end = std::chrono::steady_clock::now();
+        auto passed = std::chrono::duration_cast<std::chrono::milliseconds>(end - begin).count();
+        LOG(INFO) << "Snapshot merged in " << passed << " ms.";
+        return true;
+    }
+
+    LOG(ERROR) << "Snapshot failed to merge with state \"" << state << "\".";
+    return false;
+}
+
+static std::map<std::string, std::function<bool(int, char**)>> kCmdMap = {
+        // clang-format off
+        {"dump", DumpCmdHandler},
+        {"merge", MergeCmdHandler},
+        // clang-format on
+};
+
+}  // namespace snapshot
+}  // namespace android
+
+int main(int argc, char** argv) {
+    using namespace android::snapshot;
+    if (argc < 2) {
+        return Usage();
+    }
+
+    for (const auto& cmd : kCmdMap) {
+        if (cmd.first == argv[1]) {
+            return cmd.second(argc, argv) ? EX_OK : EX_SOFTWARE;
+        }
+    }
+
+    return Usage();
+}
diff --git a/fs_mgr/libsnapshot/snapshotctl.rc b/fs_mgr/libsnapshot/snapshotctl.rc
new file mode 100644
index 0000000..29707f1
--- /dev/null
+++ b/fs_mgr/libsnapshot/snapshotctl.rc
@@ -0,0 +1,2 @@
+on property:sys.boot_completed=1
+    exec - root root -- /system/bin/snapshotctl merge --logcat
diff --git a/init/first_stage_mount.cpp b/init/first_stage_mount.cpp
index 4a1bc5a..9121bac 100644
--- a/init/first_stage_mount.cpp
+++ b/init/first_stage_mount.cpp
@@ -50,12 +50,13 @@
 using android::fs_mgr::AvbHandleStatus;
 using android::fs_mgr::AvbHashtreeResult;
 using android::fs_mgr::AvbUniquePtr;
-using android::fs_mgr::BuildGsiSystemFstabEntry;
 using android::fs_mgr::Fstab;
 using android::fs_mgr::FstabEntry;
 using android::fs_mgr::ReadDefaultFstab;
 using android::fs_mgr::ReadFstabFromDt;
 using android::fs_mgr::SkipMountingPartitions;
+using android::fs_mgr::TransformFstabForDsu;
+using android::init::WriteFile;
 using android::snapshot::SnapshotManager;
 
 using namespace std::literals;
@@ -596,14 +597,14 @@
 }
 
 void FirstStageMount::UseGsiIfPresent() {
-    std::string metadata_file, error;
+    std::string error;
 
-    if (!android::gsi::CanBootIntoGsi(&metadata_file, &error)) {
+    if (!android::gsi::CanBootIntoGsi(&error)) {
         LOG(INFO) << "GSI " << error << ", proceeding with normal boot";
         return;
     }
 
-    auto metadata = android::fs_mgr::ReadFromImageFile(metadata_file.c_str());
+    auto metadata = android::fs_mgr::ReadFromImageFile(gsi::kDsuLpMetadataFile);
     if (!metadata) {
         LOG(ERROR) << "GSI partition layout could not be read";
         return;
@@ -627,14 +628,16 @@
         return;
     }
 
-    // Replace the existing system fstab entry.
-    auto system_partition = std::find_if(fstab_.begin(), fstab_.end(), [](const auto& entry) {
-        return entry.mount_point == "/system";
-    });
-    if (system_partition != fstab_.end()) {
-        fstab_.erase(system_partition);
+    std::string lp_names = "";
+    std::vector<std::string> dsu_partitions;
+    for (auto&& partition : metadata->partitions) {
+        auto name = fs_mgr::GetPartitionName(partition);
+        dsu_partitions.push_back(name);
+        lp_names += name + ",";
     }
-    fstab_.emplace_back(BuildGsiSystemFstabEntry());
+    // Publish the logical partition names for TransformFstabForDsu
+    WriteFile(gsi::kGsiLpNamesFile, lp_names);
+    TransformFstabForDsu(&fstab_, dsu_partitions);
     gsi_not_on_userdata_ = (super_name != "userdata");
 }
 
diff --git a/init/uevent_listener.cpp b/init/uevent_listener.cpp
index ac633776..416d942 100644
--- a/init/uevent_listener.cpp
+++ b/init/uevent_listener.cpp
@@ -171,7 +171,7 @@
     return RegenerateUeventsForDir(d.get(), callback);
 }
 
-static const char* kRegenerationPaths[] = {"/sys/class", "/sys/block", "/sys/devices"};
+static const char* kRegenerationPaths[] = {"/sys/devices"};
 
 void UeventListener::RegenerateUevents(const ListenerCallback& callback) const {
     for (const auto path : kRegenerationPaths) {
diff --git a/libpackagelistparser/Android.bp b/libpackagelistparser/Android.bp
index 0740e7d..b56dcdb 100644
--- a/libpackagelistparser/Android.bp
+++ b/libpackagelistparser/Android.bp
@@ -19,4 +19,5 @@
         "libpackagelistparser",
     ],
     test_suites: ["device-tests"],
+    require_root: true,
 }
diff --git a/libutils/include/utils/Trace.h b/libutils/include/utils/Trace.h
index 4b9c91e..fec0ffa 100644
--- a/libutils/include/utils/Trace.h
+++ b/libutils/include/utils/Trace.h
@@ -17,7 +17,12 @@
 #ifndef ANDROID_TRACE_H
 #define ANDROID_TRACE_H
 
-#if defined(__ANDROID__)
+#if defined(_WIN32)
+
+#define ATRACE_NAME(...)
+#define ATRACE_CALL()
+
+#else  // !_WIN32
 
 #include <stdint.h>
 
@@ -51,11 +56,6 @@
 
 }  // namespace android
 
-#else // !__ANDROID__
-
-#define ATRACE_NAME(...)
-#define ATRACE_CALL()
-
-#endif // __ANDROID__
+#endif  // _WIN32
 
 #endif // ANDROID_TRACE_H
diff --git a/logd/LogAudit.cpp b/logd/LogAudit.cpp
index 5a375ec..665bd38 100644
--- a/logd/LogAudit.cpp
+++ b/logd/LogAudit.cpp
@@ -160,7 +160,7 @@
     }
     auto search = denial_to_bug.find(scontext + tcontext + tclass);
     if (search != denial_to_bug.end()) {
-        bug_num->assign(" b/" + search->second);
+        bug_num->assign(" " + search->second);
     } else {
         bug_num->assign("");
     }
diff --git a/property_service/libpropertyinfoserializer/Android.bp b/property_service/libpropertyinfoserializer/Android.bp
index 51c1226..aa02a3a 100644
--- a/property_service/libpropertyinfoserializer/Android.bp
+++ b/property_service/libpropertyinfoserializer/Android.bp
@@ -1,7 +1,6 @@
 cc_defaults {
     name: "propertyinfoserializer_defaults",
     host_supported: true,
-    vendor_available: true,
     cpp_std: "experimental",
     cppflags: [
         "-Wall",
@@ -9,8 +8,8 @@
         "-Werror",
     ],
     static_libs: [
-        "libpropertyinfoparser",
         "libbase",
+        "libpropertyinfoparser",
     ],
 }
 
diff --git a/rootdir/avb/Android.bp b/rootdir/avb/Android.bp
new file mode 100644
index 0000000..85d2786
--- /dev/null
+++ b/rootdir/avb/Android.bp
@@ -0,0 +1,20 @@
+filegroup {
+    name: "q-gsi_avbpubkey",
+    srcs: [
+        "q-gsi.avbpubkey",
+    ],
+}
+
+filegroup {
+    name: "r-gsi_avbpubkey",
+    srcs: [
+        "r-gsi.avbpubkey",
+    ],
+}
+
+filegroup {
+    name: "s-gsi_avbpubkey",
+    srcs: [
+        "s-gsi.avbpubkey",
+    ],
+}
diff --git a/rootdir/etc/ld.config.legacy.txt b/rootdir/etc/ld.config.legacy.txt
index c47b7f6..bb8d4d0 100644
--- a/rootdir/etc/ld.config.legacy.txt
+++ b/rootdir/etc/ld.config.legacy.txt
@@ -179,6 +179,7 @@
 namespace.neuralnetworks.link.default.shared_libs += liblog.so
 namespace.neuralnetworks.link.default.shared_libs += libm.so
 namespace.neuralnetworks.link.default.shared_libs += libnativewindow.so
+namespace.neuralnetworks.link.default.shared_libs += libneuralnetworks_packageinfo.so
 namespace.neuralnetworks.link.default.shared_libs += libsync.so
 namespace.neuralnetworks.link.default.shared_libs += libvndksupport.so
 
diff --git a/rootdir/etc/ld.config.txt b/rootdir/etc/ld.config.txt
index 5b92d48..60035aa 100644
--- a/rootdir/etc/ld.config.txt
+++ b/rootdir/etc/ld.config.txt
@@ -420,6 +420,7 @@
 namespace.neuralnetworks.link.default.shared_libs += liblog.so
 namespace.neuralnetworks.link.default.shared_libs += libm.so
 namespace.neuralnetworks.link.default.shared_libs += libnativewindow.so
+namespace.neuralnetworks.link.default.shared_libs += libneuralnetworks_packageinfo.so
 namespace.neuralnetworks.link.default.shared_libs += libsync.so
 namespace.neuralnetworks.link.default.shared_libs += libvndksupport.so
 
@@ -641,6 +642,7 @@
 namespace.neuralnetworks.link.system.shared_libs += liblog.so
 namespace.neuralnetworks.link.system.shared_libs += libm.so
 namespace.neuralnetworks.link.system.shared_libs += libnativewindow.so
+namespace.neuralnetworks.link.system.shared_libs += libneuralnetworks_packageinfo.so
 namespace.neuralnetworks.link.system.shared_libs += libsync.so
 namespace.neuralnetworks.link.system.shared_libs += libvndksupport.so
 
@@ -782,6 +784,7 @@
 namespace.neuralnetworks.link.default.shared_libs += liblog.so
 namespace.neuralnetworks.link.default.shared_libs += libm.so
 namespace.neuralnetworks.link.default.shared_libs += libnativewindow.so
+namespace.neuralnetworks.link.default.shared_libs += libneuralnetworks_packageinfo.so
 namespace.neuralnetworks.link.default.shared_libs += libsync.so
 namespace.neuralnetworks.link.default.shared_libs += libvndksupport.so
 
diff --git a/rootdir/etc/ld.config.vndk_lite.txt b/rootdir/etc/ld.config.vndk_lite.txt
index 8a27c7b..b9b95a6 100644
--- a/rootdir/etc/ld.config.vndk_lite.txt
+++ b/rootdir/etc/ld.config.vndk_lite.txt
@@ -344,6 +344,7 @@
 namespace.neuralnetworks.link.default.shared_libs += liblog.so
 namespace.neuralnetworks.link.default.shared_libs += libm.so
 namespace.neuralnetworks.link.default.shared_libs += libnativewindow.so
+namespace.neuralnetworks.link.default.shared_libs += libneuralnetworks_packageinfo.so
 namespace.neuralnetworks.link.default.shared_libs += libsync.so
 namespace.neuralnetworks.link.default.shared_libs += libvndksupport.so
 
@@ -445,6 +446,7 @@
 namespace.neuralnetworks.link.default.shared_libs += liblog.so
 namespace.neuralnetworks.link.default.shared_libs += libm.so
 namespace.neuralnetworks.link.default.shared_libs += libnativewindow.so
+namespace.neuralnetworks.link.default.shared_libs += libneuralnetworks_packageinfo.so
 namespace.neuralnetworks.link.default.shared_libs += libsync.so
 namespace.neuralnetworks.link.default.shared_libs += libvndksupport.so
 
@@ -585,6 +587,7 @@
 namespace.neuralnetworks.link.default.shared_libs += liblog.so
 namespace.neuralnetworks.link.default.shared_libs += libm.so
 namespace.neuralnetworks.link.default.shared_libs += libnativewindow.so
+namespace.neuralnetworks.link.default.shared_libs += libneuralnetworks_packageinfo.so
 namespace.neuralnetworks.link.default.shared_libs += libsync.so
 namespace.neuralnetworks.link.default.shared_libs += libvndksupport.so
 
diff --git a/rootdir/init.environ.rc.in b/rootdir/init.environ.rc.in
index 17f6596..50005d9 100644
--- a/rootdir/init.environ.rc.in
+++ b/rootdir/init.environ.rc.in
@@ -5,7 +5,7 @@
     export ANDROID_ASSETS /system/app
     export ANDROID_DATA /data
     export ANDROID_STORAGE /storage
-    export ANDROID_RUNTIME_ROOT /apex/com.android.art
+    export ANDROID_ART_ROOT /apex/com.android.art
     export ANDROID_I18N_ROOT /apex/com.android.i18n
     export ANDROID_TZDATA_ROOT /apex/com.android.tzdata
     export EXTERNAL_STORAGE /sdcard
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 8672a38..c61fd90 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -158,6 +158,14 @@
     mkdir /mnt/user/0/self 0755 root root
     mkdir /mnt/user/0/emulated 0755 root root
     mkdir /mnt/user/0/emulated/0 0755 root root
+
+    # Prepare directories for pass through processes
+    mkdir /mnt/pass_through 0755 root root
+    mkdir /mnt/pass_through/0 0755 root root
+    mkdir /mnt/pass_through/0/self 0755 root root
+    mkdir /mnt/pass_through/0/emulated 0755 root root
+    mkdir /mnt/pass_through/0/emulated/0 0755 root root
+
     mkdir /mnt/expand 0771 system system
     mkdir /mnt/appfuse 0711 root root
 
@@ -682,6 +690,8 @@
   # Mount default storage into root namespace
   mount none /mnt/user/0 /storage bind rec
   mount none none /storage slave rec
+  # Bootstrap the emulated volume for the pass_through directory for user 0
+  mount none /data/media /mnt/pass_through/0/emulated bind rec
 on zygote-start && property:persist.sys.fuse=false
   # Mount default storage into root namespace
   mount none /mnt/runtime/default /storage bind rec