diff --git a/adb/Android.mk b/adb/Android.mk
index efdff5d..ca337ee 100644
--- a/adb/Android.mk
+++ b/adb/Android.mk
@@ -5,6 +5,8 @@
 
 LOCAL_PATH:= $(call my-dir)
 
+include $(LOCAL_PATH)/../platform_tools_tool_version.mk
+
 adb_host_sanitize :=
 adb_target_sanitize :=
 
@@ -13,7 +15,7 @@
     -Wno-unused-parameter \
     -Wno-missing-field-initializers \
     -Wvla \
-    -DADB_REVISION=\"$(BUILD_NUMBER_FROM_FILE)\" \
+    -DADB_VERSION=\"$(tool_version)\" \
 
 ADB_COMMON_posix_CFLAGS := \
     -Wexit-time-destructors \
diff --git a/adb/adb.cpp b/adb/adb.cpp
index 0181daa..c1e0d98 100644
--- a/adb/adb.cpp
+++ b/adb/adb.cpp
@@ -64,9 +64,9 @@
     // Don't change the format of this --- it's parsed by ddmlib.
     return android::base::StringPrintf(
         "Android Debug Bridge version %d.%d.%d\n"
-        "Revision %s\n"
+        "Version %s\n"
         "Installed as %s\n",
-        ADB_VERSION_MAJOR, ADB_VERSION_MINOR, ADB_SERVER_VERSION, ADB_REVISION,
+        ADB_VERSION_MAJOR, ADB_VERSION_MINOR, ADB_SERVER_VERSION, ADB_VERSION,
         android::base::GetExecutablePath().c_str());
 }
 
diff --git a/adb/daemon/main.cpp b/adb/daemon/main.cpp
index 7a87df4..a6d43ea 100644
--- a/adb/daemon/main.cpp
+++ b/adb/daemon/main.cpp
@@ -233,9 +233,8 @@
             adb_device_banner = optarg;
             break;
         case 'v':
-            printf("Android Debug Bridge Daemon version %d.%d.%d %s\n",
-                   ADB_VERSION_MAJOR, ADB_VERSION_MINOR, ADB_SERVER_VERSION,
-                   ADB_REVISION);
+            printf("Android Debug Bridge Daemon version %d.%d.%d (%s)\n", ADB_VERSION_MAJOR,
+                   ADB_VERSION_MINOR, ADB_SERVER_VERSION, ADB_VERSION);
             return 0;
         default:
             // getopt already prints "adbd: invalid option -- %c" for us.
diff --git a/fastboot/Android.mk b/fastboot/Android.mk
index e675d7d..4d54175 100644
--- a/fastboot/Android.mk
+++ b/fastboot/Android.mk
@@ -14,8 +14,12 @@
 
 LOCAL_PATH:= $(call my-dir)
 
+include $(LOCAL_PATH)/../platform_tools_tool_version.mk
+
 include $(CLEAR_VARS)
 
+LOCAL_CFLAGS += -DFASTBOOT_VERSION=\"$(tool_version)\"
+
 LOCAL_C_INCLUDES := \
   $(LOCAL_PATH)/../adb \
   $(LOCAL_PATH)/../mkbootimg \
@@ -37,8 +41,6 @@
 LOCAL_MODULE_HOST_OS := darwin linux windows
 LOCAL_CFLAGS += -Wall -Wextra -Werror -Wunreachable-code
 
-LOCAL_CFLAGS += -DFASTBOOT_REVISION=\"$(BUILD_NUMBER_FROM_FILE)\"
-
 LOCAL_SRC_FILES_linux := usb_linux.cpp
 LOCAL_STATIC_LIBRARIES_linux := libselinux
 
diff --git a/fastboot/fastboot.cpp b/fastboot/fastboot.cpp
index be7bf4a..f10b9ce 100644
--- a/fastboot/fastboot.cpp
+++ b/fastboot/fastboot.cpp
@@ -1544,7 +1544,7 @@
                 setvbuf(stdout, nullptr, _IONBF, 0);
                 setvbuf(stderr, nullptr, _IONBF, 0);
             } else if (strcmp("version", longopts[longindex].name) == 0) {
-                fprintf(stdout, "fastboot version %s\n", FASTBOOT_REVISION);
+                fprintf(stdout, "fastboot version %s\n", FASTBOOT_VERSION);
                 fprintf(stdout, "Installed as %s\n", android::base::GetExecutablePath().c_str());
                 return 0;
             } else if (strcmp("slot", longopts[longindex].name) == 0) {
diff --git a/fs_mgr/fs_mgr.cpp b/fs_mgr/fs_mgr.cpp
index 60ce43e..df3c300 100644
--- a/fs_mgr/fs_mgr.cpp
+++ b/fs_mgr/fs_mgr.cpp
@@ -744,23 +744,6 @@
     }
 }
 
-static std::string extract_by_name_prefix(struct fstab* fstab) {
-    // We assume that there's an entry for the /misc mount point in the
-    // fstab file and use that to get the device file by-name prefix.
-    // The device needs not to have an actual /misc partition.
-    // e.g.,
-    //    - /dev/block/platform/soc.0/7824900.sdhci/by-name/misc ->
-    //    - /dev/block/platform/soc.0/7824900.sdhci/by-name/
-    struct fstab_rec* fstab_entry = fs_mgr_get_entry_for_mount_point(fstab, "/misc");
-    if (fstab_entry == nullptr) {
-        LERROR << "/misc mount point not found in fstab";
-        return "";
-    }
-    std::string full_path(fstab_entry->blk_device);
-    size_t end_slash = full_path.find_last_of("/");
-    return full_path.substr(0, end_slash + 1);
-}
-
 // TODO: add ueventd notifiers if they don't exist.
 // This is just doing a wait_for_device for maximum of 1s
 int fs_mgr_test_access(const char *device) {
@@ -850,7 +833,7 @@
 
         if (fstab->recs[i].fs_mgr_flags & MF_AVB) {
             if (!avb_handle) {
-                avb_handle = FsManagerAvbHandle::Open(extract_by_name_prefix(fstab));
+                avb_handle = FsManagerAvbHandle::Open(*fstab);
                 if (!avb_handle) {
                     LERROR << "Failed to open FsManagerAvbHandle";
                     return FS_MGR_MNTALL_FAIL;
@@ -1060,7 +1043,7 @@
 
         if (fstab->recs[i].fs_mgr_flags & MF_AVB) {
             if (!avb_handle) {
-                avb_handle = FsManagerAvbHandle::Open(extract_by_name_prefix(fstab));
+                avb_handle = FsManagerAvbHandle::Open(*fstab);
                 if (!avb_handle) {
                     LERROR << "Failed to open FsManagerAvbHandle";
                     return FS_MGR_DOMNT_FAILED;
diff --git a/fs_mgr/fs_mgr_avb.cpp b/fs_mgr/fs_mgr_avb.cpp
index 31babfe..c21139e 100644
--- a/fs_mgr/fs_mgr_avb.cpp
+++ b/fs_mgr/fs_mgr_avb.cpp
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+#include "fs_mgr_avb.h"
+
 #include <errno.h>
 #include <fcntl.h>
 #include <inttypes.h>
@@ -38,9 +40,8 @@
 #include <utils/Compat.h>
 
 #include "fs_mgr.h"
-#include "fs_mgr_avb.h"
-#include "fs_mgr_avb_ops.h"
 #include "fs_mgr_priv.h"
+#include "fs_mgr_priv_avb_ops.h"
 #include "fs_mgr_priv_dm_ioctl.h"
 #include "fs_mgr_priv_sha.h"
 
@@ -457,12 +458,21 @@
     return true;
 }
 
-FsManagerAvbUniquePtr FsManagerAvbHandle::Open(const std::string& device_file_by_name_prefix) {
-    if (device_file_by_name_prefix.empty()) {
-        LERROR << "Missing device file by-name prefix";
+FsManagerAvbUniquePtr FsManagerAvbHandle::Open(const fstab& fstab) {
+    FsManagerAvbOps avb_ops(fstab);
+    return DoOpen(&avb_ops);
+}
+
+FsManagerAvbUniquePtr FsManagerAvbHandle::Open(ByNameSymlinkMap&& by_name_symlink_map) {
+    if (by_name_symlink_map.empty()) {
+        LERROR << "Empty by_name_symlink_map when opening FsManagerAvbHandle";
         return nullptr;
     }
+    FsManagerAvbOps avb_ops(std::move(by_name_symlink_map));
+    return DoOpen(&avb_ops);
+}
 
+FsManagerAvbUniquePtr FsManagerAvbHandle::DoOpen(FsManagerAvbOps* avb_ops) {
     // Gets the expected hash value of vbmeta images from kernel cmdline.
     std::unique_ptr<FsManagerAvbVerifier> avb_verifier = FsManagerAvbVerifier::Create();
     if (!avb_verifier) {
@@ -476,8 +486,7 @@
         return nullptr;
     }
 
-    FsManagerAvbOps avb_ops(device_file_by_name_prefix);
-    AvbSlotVerifyResult verify_result = avb_ops.AvbSlotVerify(
+    AvbSlotVerifyResult verify_result = avb_ops->AvbSlotVerify(
         fs_mgr_get_slot_suffix(), avb_verifier->IsDeviceUnlocked(), &avb_handle->avb_slot_data_);
 
     // Only allow two verify results:
diff --git a/fs_mgr/fs_mgr_avb_ops.cpp b/fs_mgr/fs_mgr_avb_ops.cpp
index caee4ec..8feeb53 100644
--- a/fs_mgr/fs_mgr_avb_ops.cpp
+++ b/fs_mgr/fs_mgr_avb_ops.cpp
@@ -22,6 +22,8 @@
  * SOFTWARE.
  */
 
+#include "fs_mgr_priv_avb_ops.h"
+
 #include <errno.h>
 #include <fcntl.h>
 #include <stdlib.h>
@@ -36,7 +38,6 @@
 #include <utils/Compat.h>
 
 #include "fs_mgr.h"
-#include "fs_mgr_avb_ops.h"
 #include "fs_mgr_priv.h"
 
 static AvbIOResult read_from_partition(AvbOps* ops, const char* partition, int64_t offset,
@@ -88,11 +89,7 @@
     return AVB_IO_RESULT_OK;
 }
 
-FsManagerAvbOps::FsManagerAvbOps(const std::string& device_file_by_name_prefix)
-    : device_file_by_name_prefix_(device_file_by_name_prefix) {
-    if (device_file_by_name_prefix_.back() != '/') {
-        device_file_by_name_prefix_ += '/';
-    }
+void FsManagerAvbOps::InitializeAvbOps() {
     // We only need to provide the implementation of read_from_partition()
     // operation since that's all what is being used by the avb_slot_verify().
     // Other I/O operations are only required in bootloader but not in
@@ -109,13 +106,31 @@
     avb_ops_.user_data = this;
 }
 
+FsManagerAvbOps::FsManagerAvbOps(std::map<std::string, std::string>&& by_name_symlink_map)
+    : by_name_symlink_map_(std::move(by_name_symlink_map)) {
+    InitializeAvbOps();
+}
+
+FsManagerAvbOps::FsManagerAvbOps(const fstab& fstab) {
+    // Constructs the by-name symlink map for each fstab record.
+    // /dev/block/platform/soc.0/7824900.sdhci/by-name/system_a =>
+    // by_name_symlink_map_["system_a"] = "/dev/block/platform/soc.0/7824900.sdhci/by-name/system_a"
+    for (int i = 0; i < fstab.num_entries; i++) {
+        std::string partition_name = basename(fstab.recs[i].blk_device);
+        by_name_symlink_map_[partition_name] = fstab.recs[i].blk_device;
+    }
+    InitializeAvbOps();
+}
+
 AvbIOResult FsManagerAvbOps::ReadFromPartition(const char* partition, int64_t offset,
                                                size_t num_bytes, void* buffer,
                                                size_t* out_num_read) {
-    // Appends |partition| to the device_file_by_name_prefix_, e.g.,
-    //    - /dev/block/platform/soc.0/7824900.sdhci/by-name/ ->
-    //    - /dev/block/platform/soc.0/7824900.sdhci/by-name/system_a
-    std::string path = device_file_by_name_prefix_ + partition;
+    const auto iter = by_name_symlink_map_.find(partition);
+    if (iter == by_name_symlink_map_.end()) {
+        LERROR << "by-name symlink not found for partition: '" << partition << "'";
+        return AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION;
+    }
+    std::string path = iter->second;
 
     // Ensures the device path (a symlink created by init) is ready to
     // access. fs_mgr_test_access() will test a few iterations if the
@@ -126,7 +141,7 @@
 
     android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(path.c_str(), O_RDONLY | O_CLOEXEC)));
     if (fd < 0) {
-        PERROR << "Failed to open " << path.c_str();
+        PERROR << "Failed to open " << path;
         return AVB_IO_RESULT_ERROR_IO;
     }
 
@@ -150,8 +165,7 @@
     // for EOF).
     ssize_t num_read = TEMP_FAILURE_RETRY(pread64(fd, buffer, num_bytes, offset));
     if (num_read < 0 || (size_t)num_read != num_bytes) {
-        PERROR << "Failed to read " << num_bytes << " bytes from " << path.c_str() << " offset "
-               << offset;
+        PERROR << "Failed to read " << num_bytes << " bytes from " << path << " offset " << offset;
         return AVB_IO_RESULT_ERROR_IO;
     }
 
diff --git a/fs_mgr/fs_mgr_avb_ops.h b/fs_mgr/fs_mgr_priv_avb_ops.h
similarity index 87%
rename from fs_mgr/fs_mgr_avb_ops.h
rename to fs_mgr/fs_mgr_priv_avb_ops.h
index ec4a8c9..a6b52e4 100644
--- a/fs_mgr/fs_mgr_avb_ops.h
+++ b/fs_mgr/fs_mgr_priv_avb_ops.h
@@ -22,8 +22,11 @@
  * SOFTWARE.
  */
 
-#ifndef __CORE_FS_MGR_AVB_OPS_H
-#define __CORE_FS_MGR_AVB_OPS_H
+#ifndef __CORE_FS_MGR_PRIV_AVB_OPS_H
+#define __CORE_FS_MGR_PRIV_AVB_OPS_H
+
+#include <map>
+#include <string>
 
 #include <libavb/libavb.h>
 
@@ -43,7 +46,8 @@
 //
 class FsManagerAvbOps {
   public:
-    FsManagerAvbOps(const std::string& device_file_by_name_prefix);
+    FsManagerAvbOps(const fstab& fstab);
+    FsManagerAvbOps(std::map<std::string, std::string>&& by_name_symlink_map);
 
     static FsManagerAvbOps* GetInstanceFromAvbOps(AvbOps* ops) {
         return reinterpret_cast<FsManagerAvbOps*>(ops->user_data);
@@ -56,7 +60,9 @@
                                       AvbSlotVerifyData** out_data);
 
   private:
+    void InitializeAvbOps();
+
     AvbOps avb_ops_;
-    std::string device_file_by_name_prefix_;
+    std::map<std::string, std::string> by_name_symlink_map_;
 };
-#endif /* __CORE_FS_MGR_AVB_OPS_H */
+#endif /* __CORE_FS_MGR_PRIV_AVB_OPS_H */
diff --git a/fs_mgr/include/fs_mgr_avb.h b/fs_mgr/include/fs_mgr_avb.h
index 65ff9941..bbafe1a 100644
--- a/fs_mgr/include/fs_mgr_avb.h
+++ b/fs_mgr/include/fs_mgr_avb.h
@@ -17,6 +17,7 @@
 #ifndef __CORE_FS_MGR_AVB_H
 #define __CORE_FS_MGR_AVB_H
 
+#include <map>
 #include <memory>
 #include <string>
 
@@ -31,9 +32,13 @@
     kFsManagerAvbHandleErrorVerification = 2,
 };
 
+class FsManagerAvbOps;
+
 class FsManagerAvbHandle;
 using FsManagerAvbUniquePtr = std::unique_ptr<FsManagerAvbHandle>;
 
+using ByNameSymlinkMap = std::map<std::string, std::string>;
+
 // Provides a factory method to return a unique_ptr pointing to itself and the
 // SetUpAvb() function to extract dm-verity parameters from AVB metadata to
 // load verity table into kernel through ioctl.
@@ -49,6 +54,13 @@
     // A typical usage will be:
     //   - FsManagerAvbUniquePtr handle = FsManagerAvbHandle::Open();
     //
+    // There are two overloaded Open() functions with a single parameter.
+    // The argument can be a ByNameSymlinkMap describing the mapping from partition
+    // name to by-name symlink, or a fstab file to which the ByNameSymlinkMap is
+    // constructed from. e.g.,
+    //   - /dev/block/platform/soc.0/7824900.sdhci/by-name/system_a ->
+    //   - ByNameSymlinkMap["system_a"] = "/dev/block/platform/soc.0/7824900.sdhci/by-name/system_a"
+    //
     // Possible return values:
     //   - nullptr: any error when reading and verifying the metadata,
     //     e.g., I/O error, digest value mismatch, size mismatch, etc.
@@ -61,7 +73,8 @@
     //   - a valid unique_ptr with status kFsMgrAvbHandleSuccess: the metadata
     //     is verified and can be trusted.
     //
-    static FsManagerAvbUniquePtr Open(const std::string& device_file_by_name_prefix);
+    static FsManagerAvbUniquePtr Open(const fstab& fstab);
+    static FsManagerAvbUniquePtr Open(ByNameSymlinkMap&& by_name_symlink_map);
 
     // Sets up dm-verity on the given fstab entry.
     // The 'wait_for_verity_dev' parameter makes this function wait for the
@@ -88,10 +101,10 @@
         }
     };
 
-  protected:
-    FsManagerAvbHandle() : avb_slot_data_(nullptr), status_(kFsManagerAvbHandleUninitialized) {}
-
   private:
+    FsManagerAvbHandle() : avb_slot_data_(nullptr), status_(kFsManagerAvbHandleUninitialized) {}
+    static FsManagerAvbUniquePtr DoOpen(FsManagerAvbOps* avb_ops);
+
     AvbSlotVerifyData* avb_slot_data_;
     FsManagerAvbHandleStatus status_;
     std::string avb_version_;
diff --git a/init/init_first_stage.cpp b/init/init_first_stage.cpp
index 2fa790d..9d2a0d1 100644
--- a/init/init_first_stage.cpp
+++ b/init/init_first_stage.cpp
@@ -47,18 +47,22 @@
     bool InitDevices();
 
   protected:
-    void InitRequiredDevices(std::set<std::string>* devices_partition_names);
+    void InitRequiredDevices();
     void InitVerityDevice(const std::string& verity_device);
     bool MountPartitions();
 
-    virtual bool GetRequiredDevices(std::set<std::string>* out_devices_partition_names,
-                                    bool* out_need_dm_verity) = 0;
+    virtual coldboot_action_t ColdbootCallback(uevent* uevent);
+
+    // Pure virtual functions.
+    virtual bool GetRequiredDevices() = 0;
     virtual bool SetUpDmVerity(fstab_rec* fstab_rec) = 0;
 
+    bool need_dm_verity_;
     // Device tree fstab entries.
     std::unique_ptr<fstab, decltype(&fs_mgr_free_fstab)> device_tree_fstab_;
     // Eligible first stage mount candidates, only allow /system, /vendor and/or /odm.
     std::vector<fstab_rec*> mount_fstab_recs_;
+    std::set<std::string> required_devices_partition_names_;
 };
 
 class FirstStageMountVBootV1 : public FirstStageMount {
@@ -67,27 +71,26 @@
     ~FirstStageMountVBootV1() override = default;
 
   protected:
-    bool GetRequiredDevices(std::set<std::string>* out_devices_partition_names,
-                            bool* out_need_dm_verity) override;
+    bool GetRequiredDevices() override;
     bool SetUpDmVerity(fstab_rec* fstab_rec) override;
 };
 
 class FirstStageMountVBootV2 : public FirstStageMount {
   public:
+    friend void SetInitAvbVersionInRecovery();
+
     FirstStageMountVBootV2();
     ~FirstStageMountVBootV2() override = default;
 
-    const std::string& by_name_prefix() const { return device_tree_by_name_prefix_; }
-
   protected:
-    bool GetRequiredDevices(std::set<std::string>* out_devices_partition_names,
-                            bool* out_need_dm_verity) override;
+    coldboot_action_t ColdbootCallback(uevent* uevent) override;
+    bool GetRequiredDevices() override;
     bool SetUpDmVerity(fstab_rec* fstab_rec) override;
     bool InitAvbHandle();
 
     std::string device_tree_vbmeta_parts_;
-    std::string device_tree_by_name_prefix_;
     FsManagerAvbUniquePtr avb_handle_;
+    ByNameSymlinkMap by_name_symlink_map_;
 };
 
 // Static Functions
@@ -102,7 +105,8 @@
 
 // Class Definitions
 // -----------------
-FirstStageMount::FirstStageMount() : device_tree_fstab_(fs_mgr_read_fstab_dt(), fs_mgr_free_fstab) {
+FirstStageMount::FirstStageMount()
+    : need_dm_verity_(false), device_tree_fstab_(fs_mgr_read_fstab_dt(), fs_mgr_free_fstab) {
     if (!device_tree_fstab_) {
         LOG(ERROR) << "Failed to read fstab from device tree";
         return;
@@ -136,13 +140,30 @@
 }
 
 bool FirstStageMount::InitDevices() {
-    bool need_dm_verity;
-    std::set<std::string> devices_partition_names;
+    if (!GetRequiredDevices()) return false;
 
-    // The partition name in devices_partition_names MUST have A/B suffix when A/B is used.
-    if (!GetRequiredDevices(&devices_partition_names, &need_dm_verity)) return false;
+    InitRequiredDevices();
 
-    if (need_dm_verity) {
+    // InitRequiredDevices() will remove found partitions from required_devices_partition_names_.
+    // So if it isn't empty here, it means some partitions are not found.
+    if (!required_devices_partition_names_.empty()) {
+        LOG(ERROR) << __FUNCTION__ << "(): partition(s) not found: "
+                   << android::base::Join(required_devices_partition_names_, ", ");
+        return false;
+    } else {
+        return true;
+    }
+}
+
+// Creates devices with uevent->partition_name matching one in the member variable
+// required_devices_partition_names_. Found partitions will then be removed from it
+// for the subsequent member function to check which devices are NOT created.
+void FirstStageMount::InitRequiredDevices() {
+    if (required_devices_partition_names_.empty()) {
+        return;
+    }
+
+    if (need_dm_verity_) {
         const std::string dm_path = "/devices/virtual/misc/device-mapper";
         device_init(("/sys" + dm_path).c_str(), [&dm_path](uevent* uevent) -> coldboot_action_t {
             if (uevent->path == dm_path) return COLDBOOT_STOP;
@@ -150,58 +171,40 @@
         });
     }
 
-    bool success = false;
-    InitRequiredDevices(&devices_partition_names);
-
-    // InitRequiredDevices() will remove found partitions from devices_partition_names.
-    // So if it isn't empty here, it means some partitions are not found.
-    if (!devices_partition_names.empty()) {
-        LOG(ERROR) << __FUNCTION__ << "(): partition(s) not found: "
-                   << android::base::Join(devices_partition_names, ", ");
-    } else {
-        success = true;
-    }
+    device_init(nullptr,
+                [this](uevent* uevent) -> coldboot_action_t { return ColdbootCallback(uevent); });
 
     device_close();
-    return success;
 }
 
-// Creates devices with uevent->partition_name matching one in the in/out
-// devices_partition_names. Found partitions will then be removed from the
-// devices_partition_names for the caller to check which devices are NOT created.
-void FirstStageMount::InitRequiredDevices(std::set<std::string>* devices_partition_names) {
-    if (devices_partition_names->empty()) {
-        return;
+coldboot_action_t FirstStageMount::ColdbootCallback(uevent* uevent) {
+    // We need platform devices to create symlinks.
+    if (uevent->subsystem == "platform") {
+        return COLDBOOT_CREATE;
     }
-    device_init(nullptr, [=](uevent* uevent) -> coldboot_action_t {
-        // We need platform devices to create symlinks.
-        if (uevent->subsystem == "platform") {
-            return COLDBOOT_CREATE;
-        }
 
-        // Ignores everything that is not a block device.
-        if (uevent->subsystem != "block") {
-            return COLDBOOT_CONTINUE;
-        }
+    // Ignores everything that is not a block device.
+    if (uevent->subsystem != "block") {
+        return COLDBOOT_CONTINUE;
+    }
 
-        if (!uevent->partition_name.empty()) {
-            // Matches partition name to create device nodes.
-            // Both devices_partition_names and uevent->partition_name have A/B
-            // suffix when A/B is used.
-            auto iter = devices_partition_names->find(uevent->partition_name);
-            if (iter != devices_partition_names->end()) {
-                LOG(VERBOSE) << __FUNCTION__ << "(): found partition: " << *iter;
-                devices_partition_names->erase(iter);
-                if (devices_partition_names->empty()) {
-                    return COLDBOOT_STOP;  // Found all partitions, stop coldboot.
-                } else {
-                    return COLDBOOT_CREATE;  // Creates this device and continue to find others.
-                }
+    if (!uevent->partition_name.empty()) {
+        // Matches partition name to create device nodes.
+        // Both required_devices_partition_names_ and uevent->partition_name have A/B
+        // suffix when A/B is used.
+        auto iter = required_devices_partition_names_.find(uevent->partition_name);
+        if (iter != required_devices_partition_names_.end()) {
+            LOG(VERBOSE) << __FUNCTION__ << "(): found partition: " << *iter;
+            required_devices_partition_names_.erase(iter);
+            if (required_devices_partition_names_.empty()) {
+                return COLDBOOT_STOP;  // Found all partitions, stop coldboot.
+            } else {
+                return COLDBOOT_CREATE;  // Creates this device and continue to find others.
             }
         }
-        // Not found a partition or find an unneeded partition, continue to find others.
-        return COLDBOOT_CONTINUE;
-    });
+    }
+    // Not found a partition or find an unneeded partition, continue to find others.
+    return COLDBOOT_CONTINUE;
 }
 
 // Creates "/dev/block/dm-XX" for dm-verity by running coldboot on /sys/block/dm-XX.
@@ -233,10 +236,9 @@
     return true;
 }
 
-bool FirstStageMountVBootV1::GetRequiredDevices(std::set<std::string>* out_devices_partition_names,
-                                                bool* out_need_dm_verity) {
+bool FirstStageMountVBootV1::GetRequiredDevices() {
     std::string verity_loc_device;
-    *out_need_dm_verity = false;
+    need_dm_verity_ = false;
 
     for (auto fstab_rec : mount_fstab_recs_) {
         // Don't allow verifyatboot in the first stage.
@@ -246,7 +248,7 @@
         }
         // Checks for verified partitions.
         if (fs_mgr_is_verified(fstab_rec)) {
-            *out_need_dm_verity = true;
+            need_dm_verity_ = true;
         }
         // Checks if verity metadata is on a separate partition. Note that it is
         // not partition specific, so there must be only one additional partition
@@ -265,11 +267,11 @@
     // Includes the partition names of fstab records and verity_loc_device (if any).
     // Notes that fstab_rec->blk_device has A/B suffix updated by fs_mgr when A/B is used.
     for (auto fstab_rec : mount_fstab_recs_) {
-        out_devices_partition_names->emplace(basename(fstab_rec->blk_device));
+        required_devices_partition_names_.emplace(basename(fstab_rec->blk_device));
     }
 
     if (!verity_loc_device.empty()) {
-        out_devices_partition_names->emplace(basename(verity_loc_device.c_str()));
+        required_devices_partition_names_.emplace(basename(verity_loc_device.c_str()));
     }
 
     return true;
@@ -292,15 +294,13 @@
 }
 
 // FirstStageMountVBootV2 constructor.
-// Gets the vbmeta configurations from device tree.
-// Specifically, the 'parts' and 'by_name_prefix' below.
+// Gets the vbmeta partitions from device tree.
 // /{
 //     firmware {
 //         android {
 //             vbmeta {
 //                 compatible = "android,vbmeta";
 //                 parts = "vbmeta,boot,system,vendor"
-//                 by_name_prefix = "/dev/block/platform/soc.0/f9824900.sdhci/by-name/"
 //             };
 //         };
 //     };
@@ -310,31 +310,24 @@
         PLOG(ERROR) << "Failed to read vbmeta/parts from device tree";
         return;
     }
-
-    // TODO: removes by_name_prefix to allow partitions on different block devices.
-    if (!read_android_dt_file("vbmeta/by_name_prefix", &device_tree_by_name_prefix_)) {
-        PLOG(ERROR) << "Failed to read vbmeta/by_name_prefix from dt";
-        return;
-    }
 }
 
-bool FirstStageMountVBootV2::GetRequiredDevices(std::set<std::string>* out_devices_partition_names,
-                                                bool* out_need_dm_verity) {
-    *out_need_dm_verity = false;
+bool FirstStageMountVBootV2::GetRequiredDevices() {
+    need_dm_verity_ = false;
 
     // fstab_rec->blk_device has A/B suffix.
     for (auto fstab_rec : mount_fstab_recs_) {
         if (fs_mgr_is_avb(fstab_rec)) {
-            *out_need_dm_verity = true;
+            need_dm_verity_ = true;
         }
-        out_devices_partition_names->emplace(basename(fstab_rec->blk_device));
+        required_devices_partition_names_.emplace(basename(fstab_rec->blk_device));
     }
 
     // libavb verifies AVB metadata on all verified partitions at once.
     // e.g., The device_tree_vbmeta_parts_ will be "vbmeta,boot,system,vendor"
     // for libavb to verify metadata, even if there is only /vendor in the
     // above mount_fstab_recs_.
-    if (*out_need_dm_verity) {
+    if (need_dm_verity_) {
         if (device_tree_vbmeta_parts_.empty()) {
             LOG(ERROR) << "Missing vbmeta parts in device tree";
             return false;
@@ -342,16 +335,45 @@
         std::vector<std::string> partitions = android::base::Split(device_tree_vbmeta_parts_, ",");
         std::string ab_suffix = fs_mgr_get_slot_suffix();
         for (const auto& partition : partitions) {
-            // out_devices_partition_names is of type std::set so it's not an issue to emplace
-            // a partition twice. e.g., /vendor might be in both places:
+            // required_devices_partition_names_ is of type std::set so it's not an issue
+            // to emplace a partition twice. e.g., /vendor might be in both places:
             //   - device_tree_vbmeta_parts_ = "vbmeta,boot,system,vendor"
             //   - mount_fstab_recs_: /vendor_a
-            out_devices_partition_names->emplace(partition + ab_suffix);
+            required_devices_partition_names_.emplace(partition + ab_suffix);
         }
     }
     return true;
 }
 
+coldboot_action_t FirstStageMountVBootV2::ColdbootCallback(uevent* uevent) {
+    // Invokes the parent function to see if any desired partition has been found.
+    // If yes, record the by-name symlink for creating FsManagerAvbHandle later.
+    coldboot_action_t parent_callback_ret = FirstStageMount::ColdbootCallback(uevent);
+
+    // Skips the uevent if the parent function returns COLDBOOT_CONTINUE (meaning
+    // that the uevent was skipped) or there is no uevent->partition_name to
+    // create the by-name symlink.
+    if (parent_callback_ret != COLDBOOT_CONTINUE && !uevent->partition_name.empty()) {
+        // get_block_device_symlinks() will return three symlinks at most, depending on
+        // the content of uevent. by-name symlink will be at [0] if uevent->partition_name
+        // is not empty. e.g.,
+        //   - /dev/block/platform/soc.0/f9824900.sdhci/by-name/modem
+        //   - /dev/block/platform/soc.0/f9824900.sdhci/by-num/p1
+        //   - /dev/block/platform/soc.0/f9824900.sdhci/mmcblk0p1
+        std::vector<std::string> links = get_block_device_symlinks(uevent);
+        if (!links.empty()) {
+            auto[it, inserted] = by_name_symlink_map_.emplace(uevent->partition_name, links[0]);
+            if (!inserted) {
+                LOG(ERROR) << "Partition '" << uevent->partition_name
+                           << "' already existed in the by-name symlink map with a value of '"
+                           << it->second << "', new value '" << links[0] << "' will be ignored.";
+            }
+        }
+    }
+
+    return parent_callback_ret;
+}
+
 bool FirstStageMountVBootV2::SetUpDmVerity(fstab_rec* fstab_rec) {
     if (fs_mgr_is_avb(fstab_rec)) {
         if (!InitAvbHandle()) return false;
@@ -371,7 +393,14 @@
 bool FirstStageMountVBootV2::InitAvbHandle() {
     if (avb_handle_) return true;  // Returns true if the handle is already initialized.
 
-    avb_handle_ = FsManagerAvbHandle::Open(device_tree_by_name_prefix_);
+    if (by_name_symlink_map_.empty()) {
+        LOG(ERROR) << "by_name_symlink_map_ is empty";
+        return false;
+    }
+
+    avb_handle_ = FsManagerAvbHandle::Open(std::move(by_name_symlink_map_));
+    by_name_symlink_map_.clear();  // Removes all elements after the above std::move().
+
     if (!avb_handle_) {
         PLOG(ERROR) << "Failed to open FsManagerAvbHandle";
         return false;
@@ -427,7 +456,8 @@
         return;
     }
 
-    FsManagerAvbUniquePtr avb_handle = FsManagerAvbHandle::Open(avb_first_mount.by_name_prefix());
+    FsManagerAvbUniquePtr avb_handle =
+        FsManagerAvbHandle::Open(std::move(avb_first_mount.by_name_symlink_map_));
     if (!avb_handle) {
         PLOG(ERROR) << "Failed to open FsManagerAvbHandle for INIT_AVB_VERSION";
         return;
diff --git a/platform_tools_tool_version.mk b/platform_tools_tool_version.mk
new file mode 100644
index 0000000..73229e6
--- /dev/null
+++ b/platform_tools_tool_version.mk
@@ -0,0 +1,22 @@
+# Copyright (C) 2017 Google Inc.
+#
+# 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.
+
+# We rewrite ${PLATFORM_SDK_VERSION} with 0 rather than $(PLATFORM_SDK_VERSION)
+# because on the actual platform tools release branches the file contains a
+# literal instead. Using 0 lets us easily distinguish non-canonical builds.
+platform_tools_version := $(shell sed \
+    's/$${PLATFORM_SDK_VERSION}/0/ ; s/^Pkg.Revision=\(.*\)/\1/p ; d' \
+    $(ANDROID_BUILD_TOP)/development/sdk/plat_tools_source.prop_template \
+  )
+tool_version := $(platform_tools_version)-$(BUILD_NUMBER_FROM_FILE)