diff --git a/adb/Android.bp b/adb/Android.bp
index 81d20c1..a557090 100644
--- a/adb/Android.bp
+++ b/adb/Android.bp
@@ -114,6 +114,46 @@
     },
 }
 
+cc_defaults {
+    name: "libadbd_binary_dependencies",
+    static_libs: [
+        "libadb_crypto",
+        "libadb_pairing_connection",
+        "libadb_tls_connection",
+        "libadbd",
+        "libadbd_core",
+        "libadbconnection_server",
+        "libasyncio",
+        "libbrotli",
+        "libcutils_sockets",
+        "libdiagnose_usb",
+        "libmdnssd",
+        "libbase",
+
+        "libadb_protos",
+        "libapp_processes_protos_lite",
+        "libprotobuf-cpp-lite",
+    ],
+
+    shared_libs: [
+        "libadbd_auth",
+        "libadbd_fs",
+        "libcrypto",
+        "libcrypto_utils",
+        "liblog",
+        "libselinux",
+    ],
+
+    target: {
+        recovery: {
+            exclude_static_libs: [
+                "libadb_pairing_auth",
+                "libadb_pairing_connection",
+            ],
+        },
+    },
+}
+
 // libadb
 // =========================================================
 // These files are compiled for both the host and the device.
@@ -133,7 +173,6 @@
     "transport.cpp",
     "transport_fd.cpp",
     "transport_local.cpp",
-    "transport_usb.cpp",
     "types.cpp",
 ]
 
@@ -169,6 +208,7 @@
         "client/usb_libusb.cpp",
         "client/usb_dispatch.cpp",
         "client/transport_mdns.cpp",
+        "client/transport_usb.cpp",
         "client/pairing/pairing_client.cpp",
     ],
 
@@ -246,39 +286,6 @@
     },
 }
 
-cc_benchmark {
-    name: "adb_benchmark",
-    defaults: ["adb_defaults"],
-
-    srcs: ["transport_benchmark.cpp"],
-    target: {
-        android: {
-            static_libs: [
-                "libadbd",
-            ],
-        },
-        host: {
-            static_libs: [
-                "libadb_host",
-            ],
-        },
-    },
-
-    static_libs: [
-        "libadb_crypto_static",
-        "libadb_tls_connection_static",
-        "libadbd_auth",
-        "libbase",
-        "libcutils",
-        "libcrypto_utils",
-        "libcrypto_static",
-        "libdiagnose_usb",
-        "liblog",
-        "libssl",
-        "libusb",
-    ],
-}
-
 cc_binary_host {
     name: "adb",
 
@@ -382,10 +389,6 @@
         "daemon/adb_wifi.cpp",
     ],
 
-    local_include_dirs: [
-        "daemon/include",
-    ],
-
     generated_headers: ["platform_tools_version"],
 
     static_libs: [
@@ -404,6 +407,7 @@
         "libbase",
         "libcrypto",
         "libcrypto_utils",
+        "libcutils_sockets",
         "liblog",
     ],
 
@@ -422,12 +426,6 @@
                 "daemon/transport_qemu.cpp",
                 "daemon/usb.cpp",
                 "daemon/usb_ffs.cpp",
-                "daemon/usb_legacy.cpp",
-            ]
-        },
-        linux_glibc: {
-            srcs: [
-                "daemon/usb_dummy.cpp",
             ]
         },
         recovery: {
@@ -479,16 +477,18 @@
         "libadb_pairing_connection",
         "libadb_protos",
         "libadb_tls_connection",
-        "libadbd_auth",
-        "libadbd_fs",
         "libapp_processes_protos_lite",
         "libasyncio",
         "libbase",
-        "libcrypto",
         "libcrypto_utils",
         "libcutils_sockets",
-        "liblog",
         "libprotobuf-cpp-lite",
+
+        // APEX dependencies.
+        "libadbd_auth",
+        "libadbd_fs",
+        "libcrypto",
+        "liblog",
     ],
 
     target: {
@@ -537,10 +537,6 @@
     // libminadbd wants both, as it's used to build native tests.
     compile_multilib: "both",
 
-    whole_static_libs: [
-        "libadbd_core",
-    ],
-
     shared_libs: [
         "libadbconnection_server",
         "libapp_processes_protos_lite",
@@ -548,15 +544,17 @@
         "libadb_crypto",
         "libadb_pairing_connection",
         "libadb_tls_connection",
-        "libadbd_auth",
-        "libadbd_fs",
-        "libadbd_services",
         "libasyncio",
         "libbase",
         "libcrypto",
         "libcrypto_utils",
         "liblog",
         "libselinux",
+
+        // APEX dependencies on the system image.
+        "libadbd_auth",
+        "libadbd_fs",
+        "libadbd_services",
     ],
 
     target: {
@@ -569,20 +567,22 @@
     },
 
     static_libs: [
+        "libadbd_core",
         "libbrotli",
         "libcutils_sockets",
         "libdiagnose_usb",
         "libmdnssd",
     ],
 
-    export_include_dirs: [
-        "daemon/include",
+    visibility: [
+        "//bootable/recovery/minadbd",
+        "//system/core/adb",
     ],
 }
 
 cc_binary {
     name: "adbd",
-    defaults: ["adbd_defaults", "host_adbd_supported"],
+    defaults: ["adbd_defaults", "host_adbd_supported", "libadbd_binary_dependencies"],
     stl: "libc++_static",
     recovery_available: true,
     apex_available: ["com.android.adbd"],
@@ -601,33 +601,17 @@
     },
 
     static_libs: [
-        "libadb_crypto",
-        "libadb_tls_connection",
-        "libadbconnection_server",
         "libadbd",
         "libadbd_services",
-        "libapp_processes_protos_lite",
         "libasyncio",
-        "libbase",
-        "libbrotli",
         "libcap",
-        "libcrypto_utils",
-        "libcutils_sockets",
-        "libdiagnose_usb",
-        "libmdnssd",
         "libminijail",
-        "libprotobuf-cpp-lite",
         "libssl",
     ],
 
     shared_libs: [
-        "libadb_pairing_connection",
         "libadb_protos",
         "libadbd_auth",
-        "libadbd_fs",
-        "libcrypto",
-        "liblog",
-        "libselinux",
     ],
 
     target: {
@@ -699,8 +683,7 @@
 cc_test {
     name: "adbd_test",
 
-    defaults: ["adbd_defaults"],
-    stl: "libc++_static",
+    defaults: ["adbd_defaults", "libadbd_binary_dependencies"],
 
     recovery_available: false,
     srcs: libadb_test_srcs + [
@@ -711,21 +694,16 @@
         "shell_service_protocol_test.cpp",
     ],
 
+    shared_libs: [
+        "liblog",
+    ],
+
     static_libs: [
         "libadbd",
         "libadbd_auth",
-        "libadb_crypto_static",
-        "libadb_pairing_connection_static",
-        "libadb_tls_connection_static",
         "libbase",
         "libcrypto_utils",
-        "libcrypto_static",
-        "libcutils_sockets",
-        "libdiagnose_usb",
-        "liblog",
         "libusb",
-        "libmdnssd",
-        "libselinux",
     ],
     test_suites: ["device-tests", "mts"],
     require_root: true,
diff --git a/adb/adb.cpp b/adb/adb.cpp
index b514368..6c03f74 100644
--- a/adb/adb.cpp
+++ b/adb/adb.cpp
@@ -66,6 +66,10 @@
 #include "daemon/logging.h"
 #endif
 
+#if ADB_HOST
+#include "client/usb.h"
+#endif
+
 std::string adb_version() {
     // Don't change the format of this --- it's parsed by ddmlib.
     return android::base::StringPrintf(
diff --git a/adb/adb.h b/adb/adb.h
index 9f8d299..7bc60fc 100644
--- a/adb/adb.h
+++ b/adb/adb.h
@@ -29,7 +29,6 @@
 #include "fdevent/fdevent.h"
 #include "socket.h"
 #include "types.h"
-#include "usb.h"
 
 constexpr size_t MAX_PAYLOAD_V1 = 4 * 1024;
 constexpr size_t MAX_PAYLOAD = 1024 * 1024;
@@ -139,7 +138,6 @@
 
 /* initialize a transport object's func pointers and state */
 int init_socket_transport(atransport* t, unique_fd s, int port, int local);
-void init_usb_transport(atransport* t, usb_handle* usb);
 
 std::string getEmulatorSerialString(int console_port);
 #if ADB_HOST
@@ -253,4 +251,5 @@
 // Wait until device scan has completed and every transport is ready, or a timeout elapses.
 void adb_wait_for_device_initialization();
 
+void usb_init();
 #endif
diff --git a/adb/client/main.cpp b/adb/client/main.cpp
index 33e0716..4a9eadc 100644
--- a/adb/client/main.cpp
+++ b/adb/client/main.cpp
@@ -36,6 +36,7 @@
 #include "adb_listeners.h"
 #include "adb_utils.h"
 #include "adb_wifi.h"
+#include "client/usb.h"
 #include "commandline.h"
 #include "sysdeps/chrono.h"
 #include "transport.h"
diff --git a/adb/transport_usb.cpp b/adb/client/transport_usb.cpp
similarity index 96%
rename from adb/transport_usb.cpp
rename to adb/client/transport_usb.cpp
index fb81b37..777edde 100644
--- a/adb/transport_usb.cpp
+++ b/adb/client/transport_usb.cpp
@@ -16,6 +16,10 @@
 
 #define TRACE_TAG TRANSPORT
 
+#include "sysdeps.h"
+
+#include "client/usb.h"
+
 #include <memory>
 
 #include "sysdeps.h"
@@ -135,8 +139,8 @@
         }
 
         p->payload.resize(p->msg.data_length);
-        if (usb_read(usb, &p->payload[0], p->payload.size())
-                != static_cast<int>(p->payload.size())) {
+        if (usb_read(usb, &p->payload[0], p->payload.size()) !=
+            static_cast<int>(p->payload.size())) {
             PLOG(ERROR) << "remote usb: terminated (data)";
             return -1;
         }
diff --git a/adb/usb.h b/adb/client/usb.h
similarity index 72%
rename from adb/usb.h
rename to adb/client/usb.h
index eb8ca6c..b371788 100644
--- a/adb/usb.h
+++ b/adb/client/usb.h
@@ -18,6 +18,9 @@
 
 #include <sys/types.h>
 
+#include "adb.h"
+#include "transport.h"
+
 // USB host/client interface.
 
 #define ADB_USB_INTERFACE(handle_ref_type)                       \
@@ -30,35 +33,38 @@
     void usb_kick(handle_ref_type h);                            \
     size_t usb_get_max_packet_size(handle_ref_type)
 
-#if !ADB_HOST
-// The daemon has a single implementation.
-
-struct usb_handle;
-ADB_USB_INTERFACE(usb_handle*);
-
-#else // linux host || darwin
 // Linux and Darwin clients have native and libusb implementations.
 
 namespace libusb {
-    struct usb_handle;
-    ADB_USB_INTERFACE(libusb::usb_handle*);
-}
+struct usb_handle;
+ADB_USB_INTERFACE(libusb::usb_handle*);
+}  // namespace libusb
 
 namespace native {
-    struct usb_handle;
-    ADB_USB_INTERFACE(native::usb_handle*);
-}
+struct usb_handle;
+ADB_USB_INTERFACE(native::usb_handle*);
+}  // namespace native
 
 // Empty base that both implementations' opaque handles inherit from.
-struct usb_handle {
-};
+struct usb_handle {};
 
 ADB_USB_INTERFACE(::usb_handle*);
 
-#endif // linux host || darwin
-
-
 // USB device detection.
 int is_adb_interface(int usb_class, int usb_subclass, int usb_protocol);
 
 bool should_use_libusb();
+
+struct UsbConnection : public BlockingConnection {
+    explicit UsbConnection(usb_handle* handle) : handle_(handle) {}
+    ~UsbConnection();
+
+    bool Read(apacket* packet) override final;
+    bool Write(apacket* packet) override final;
+    bool DoTlsHandshake(RSA* key, std::string* auth_key) override final;
+
+    void Close() override final;
+    virtual void Reset() override final;
+
+    usb_handle* handle_;
+};
diff --git a/adb/client/usb_dispatch.cpp b/adb/client/usb_dispatch.cpp
index f55ae90..7b97117 100644
--- a/adb/client/usb_dispatch.cpp
+++ b/adb/client/usb_dispatch.cpp
@@ -15,7 +15,8 @@
  */
 
 #include <android-base/logging.h>
-#include "usb.h"
+
+#include "client/usb.h"
 
 void usb_init() {
     if (should_use_libusb()) {
diff --git a/adb/client/usb_libusb.cpp b/adb/client/usb_libusb.cpp
index 53f01a0..07cbc94 100644
--- a/adb/client/usb_libusb.cpp
+++ b/adb/client/usb_libusb.cpp
@@ -14,10 +14,10 @@
  * limitations under the License.
  */
 
-#include "usb.h"
-
 #include "sysdeps.h"
 
+#include "client/usb.h"
+
 #include <stdint.h>
 #include <stdlib.h>
 
@@ -40,7 +40,6 @@
 #include "adb.h"
 #include "adb_utils.h"
 #include "transport.h"
-#include "usb.h"
 
 using android::base::StringPrintf;
 
diff --git a/adb/client/usb_linux.cpp b/adb/client/usb_linux.cpp
index 343e7b5..95b1817 100644
--- a/adb/client/usb_linux.cpp
+++ b/adb/client/usb_linux.cpp
@@ -18,6 +18,8 @@
 
 #include "sysdeps.h"
 
+#include "client/usb.h"
+
 #include <ctype.h>
 #include <dirent.h>
 #include <errno.h>
@@ -48,7 +50,6 @@
 
 #include "adb.h"
 #include "transport.h"
-#include "usb.h"
 
 using namespace std::chrono_literals;
 using namespace std::literals;
diff --git a/adb/client/usb_osx.cpp b/adb/client/usb_osx.cpp
index 7207ca7..a93fa3a 100644
--- a/adb/client/usb_osx.cpp
+++ b/adb/client/usb_osx.cpp
@@ -18,6 +18,8 @@
 
 #include "sysdeps.h"
 
+#include "client/usb.h"
+
 #include <CoreFoundation/CoreFoundation.h>
 
 #include <IOKit/IOKitLib.h>
diff --git a/adb/client/usb_windows.cpp b/adb/client/usb_windows.cpp
index 197c6fa..e209230 100644
--- a/adb/client/usb_windows.cpp
+++ b/adb/client/usb_windows.cpp
@@ -18,6 +18,8 @@
 
 #include "sysdeps.h"
 
+#include "client/usb.h"
+
 // clang-format off
 #include <winsock2.h>  // winsock.h *must* be included before windows.h.
 #include <windows.h>
diff --git a/adb/crypto/Android.bp b/adb/crypto/Android.bp
index ce1de4a..9d14b03 100644
--- a/adb/crypto/Android.bp
+++ b/adb/crypto/Android.bp
@@ -40,6 +40,7 @@
 
     visibility: [
         "//system/core/adb:__subpackages__",
+        "//bootable/recovery/minadbd:__subpackages__",
     ],
 
     host_supported: true,
diff --git a/adb/daemon/usb.cpp b/adb/daemon/usb.cpp
index 87937fb..7fff05a 100644
--- a/adb/daemon/usb.cpp
+++ b/adb/daemon/usb.cpp
@@ -45,19 +45,15 @@
 #include <android-base/properties.h>
 #include <android-base/thread_annotations.h>
 
-#include <adbd/usb.h>
-
 #include "adb_unique_fd.h"
 #include "adb_utils.h"
+#include "daemon/usb_ffs.h"
 #include "sysdeps/chrono.h"
 #include "transport.h"
 #include "types.h"
 
 using android::base::StringPrintf;
 
-// We can't find out whether we have support for AIO on ffs endpoints until we submit a read.
-static std::optional<bool> gFfsAioSupported;
-
 // Not all USB controllers support operations larger than 16k, so don't go above that.
 // Also, each submitted operation does an allocation in the kernel of that size, so we want to
 // minimize our queue depth while still maintaining a deep enough queue to keep the USB stack fed.
@@ -612,17 +608,10 @@
         block->pending = true;
         struct iocb* iocb = &block->control;
         if (io_submit(aio_context_.get(), 1, &iocb) != 1) {
-            if (errno == EINVAL && !gFfsAioSupported.has_value()) {
-                HandleError("failed to submit first read, AIO on FFS not supported");
-                gFfsAioSupported = false;
-                return false;
-            }
-
             HandleError(StringPrintf("failed to submit read: %s", strerror(errno)));
             return false;
         }
 
-        gFfsAioSupported = true;
         return true;
     }
 
@@ -741,17 +730,10 @@
     static constexpr int kInterruptionSignal = SIGUSR1;
 };
 
-void usb_init_legacy();
-
 static void usb_ffs_open_thread() {
     adb_thread_setname("usb ffs open");
 
     while (true) {
-        if (gFfsAioSupported.has_value() && !gFfsAioSupported.value()) {
-            LOG(INFO) << "failed to use nonblocking ffs, falling back to legacy";
-            return usb_init_legacy();
-        }
-
         unique_fd control;
         unique_fd bulk_out;
         unique_fd bulk_in;
@@ -773,13 +755,5 @@
 }
 
 void usb_init() {
-    bool use_nonblocking = android::base::GetBoolProperty(
-            "persist.adb.nonblocking_ffs",
-            android::base::GetBoolProperty("ro.adb.nonblocking_ffs", true));
-
-    if (use_nonblocking) {
-        std::thread(usb_ffs_open_thread).detach();
-    } else {
-        usb_init_legacy();
-    }
+    std::thread(usb_ffs_open_thread).detach();
 }
diff --git a/adb/daemon/usb_dummy.cpp b/adb/daemon/usb_dummy.cpp
deleted file mode 100644
index c9bf797..0000000
--- a/adb/daemon/usb_dummy.cpp
+++ /dev/null
@@ -1,42 +0,0 @@
-/*
- * 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 <adbd/usb.h>
-
-#include <android-base/logging.h>
-
-int usb_write(usb_handle*, const void*, int) {
-    LOG(FATAL) << "unimplemented";
-    return -1;
-}
-
-int usb_read(usb_handle*, void*, int) {
-    LOG(FATAL) << "unimplemented";
-    return -1;
-}
-
-int usb_close(usb_handle*) {
-    LOG(FATAL) << "unimplemented";
-    return -1;
-}
-
-void usb_reset(usb_handle*) {
-    LOG(FATAL) << "unimplemented";
-}
-
-void usb_kick(usb_handle*) {
-    LOG(FATAL) << "unimplemented";
-}
diff --git a/adb/daemon/usb_ffs.cpp b/adb/daemon/usb_ffs.cpp
index cb7e2fb..7bd611b 100644
--- a/adb/daemon/usb_ffs.cpp
+++ b/adb/daemon/usb_ffs.cpp
@@ -18,6 +18,8 @@
 
 #include "sysdeps.h"
 
+#include "daemon/usb_ffs.h"
+
 #include <linux/usb/ch9.h>
 #include <linux/usb/functionfs.h>
 
@@ -26,7 +28,6 @@
 #include <android-base/unique_fd.h>
 
 #include "adb.h"
-#include "adbd/usb.h"
 
 #define MAX_PACKET_SIZE_FS 64
 #define MAX_PACKET_SIZE_HS 512
diff --git a/adb/daemon/usb_ffs.h b/adb/daemon/usb_ffs.h
new file mode 100644
index 0000000..a19d7cc
--- /dev/null
+++ b/adb/daemon/usb_ffs.h
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2020 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 <android-base/unique_fd.h>
+
+bool open_functionfs(android::base::unique_fd* control, android::base::unique_fd* bulk_out,
+                     android::base::unique_fd* bulk_in);
diff --git a/adb/pairing_connection/Android.bp b/adb/pairing_connection/Android.bp
index bcde7b1..707161b 100644
--- a/adb/pairing_connection/Android.bp
+++ b/adb/pairing_connection/Android.bp
@@ -41,6 +41,9 @@
         "//art:__subpackages__",
         "//system/core/adb:__subpackages__",
         "//frameworks/base/services:__subpackages__",
+
+        // This needs to be visible to minadbd, even though it's removed via exclude_shared_libs.
+        "//bootable/recovery/minadbd:__subpackages__",
     ],
     apex_available: [
         "com.android.adbd",
diff --git a/adb/proto/Android.bp b/adb/proto/Android.bp
index fe828a0..086d10e 100644
--- a/adb/proto/Android.bp
+++ b/adb/proto/Android.bp
@@ -41,6 +41,9 @@
 
     visibility: [
         "//system/core/adb:__subpackages__",
+
+        // This needs to be visible to minadbd, even though it's removed via exclude_shared_libs.
+        "//bootable/recovery/minadbd:__subpackages__",
     ],
 
     stl: "libc++_static",
@@ -92,6 +95,9 @@
 
     visibility: [
         "//system/core/adb:__subpackages__",
+
+        // This needs to be visible to minadbd, even though it's removed via exclude_shared_libs.
+        "//bootable/recovery/minadbd:__subpackages__",
     ],
 
     stl: "libc++_static",
diff --git a/adb/tls/Android.bp b/adb/tls/Android.bp
index f2837e1..e5204f3 100644
--- a/adb/tls/Android.bp
+++ b/adb/tls/Android.bp
@@ -39,6 +39,7 @@
     recovery_available: true,
 
     visibility: [
+        "//bootable/recovery/minadbd:__subpackages__",
         "//system/core/adb:__subpackages__",
     ],
 
diff --git a/adb/transport.cpp b/adb/transport.cpp
index 6dccb7f..e06dbe3 100644
--- a/adb/transport.cpp
+++ b/adb/transport.cpp
@@ -1452,6 +1452,7 @@
 
 #endif
 
+#if ADB_HOST
 void register_usb_transport(usb_handle* usb, const char* serial, const char* devpath,
                             unsigned writeable) {
     atransport* t = new atransport(writeable ? kCsOffline : kCsNoPerm);
@@ -1473,6 +1474,7 @@
 
     register_transport(t);
 }
+#endif
 
 #if ADB_HOST
 // This should only be used for transports with connection_state == kCsNoPerm.
diff --git a/adb/transport.h b/adb/transport.h
index 3a77cf6..b1984db 100644
--- a/adb/transport.h
+++ b/adb/transport.h
@@ -39,7 +39,6 @@
 #include "adb.h"
 #include "adb_unique_fd.h"
 #include "types.h"
-#include "usb.h"
 
 typedef std::unordered_set<std::string> FeatureSet;
 
@@ -204,20 +203,6 @@
     std::unique_ptr<adb::tls::TlsConnection> tls_;
 };
 
-struct UsbConnection : public BlockingConnection {
-    explicit UsbConnection(usb_handle* handle) : handle_(handle) {}
-    ~UsbConnection();
-
-    bool Read(apacket* packet) override final;
-    bool Write(apacket* packet) override final;
-    bool DoTlsHandshake(RSA* key, std::string* auth_key) override final;
-
-    void Close() override final;
-    virtual void Reset() override final;
-
-    usb_handle* handle_;
-};
-
 // Waits for a transport's connection to be not pending. This is a separate
 // object so that the transport can be destroyed and another thread can be
 // notified of it in a race-free way.
@@ -253,6 +238,10 @@
     Abort,
 };
 
+#if ADB_HOST
+struct usb_handle;
+#endif
+
 class atransport : public enable_weak_from_this<atransport> {
   public:
     // TODO(danalbert): We expose waaaaaaay too much stuff because this was
@@ -293,8 +282,10 @@
         return connection_;
     }
 
+#if ADB_HOST
     void SetUsbHandle(usb_handle* h) { usb_handle_ = h; }
     usb_handle* GetUsbHandle() { return usb_handle_; }
+#endif
 
     const TransportId id;
 
@@ -401,8 +392,10 @@
     // The underlying connection object.
     std::shared_ptr<Connection> connection_ GUARDED_BY(mutex_);
 
+#if ADB_HOST
     // USB handle for the connection, if available.
     usb_handle* usb_handle_ = nullptr;
+#endif
 
     // A callback that will be invoked when the atransport needs to reconnect.
     ReconnectCallback reconnect_;
@@ -443,8 +436,15 @@
 #endif
 
 void register_transport(atransport* transport);
-void register_usb_transport(usb_handle* h, const char* serial,
-                            const char* devpath, unsigned writeable);
+
+#if ADB_HOST
+void init_usb_transport(atransport* t, usb_handle* usb);
+void register_usb_transport(usb_handle* h, const char* serial, const char* devpath,
+                            unsigned writeable);
+
+// This should only be used for transports with connection_state == kCsNoPerm.
+void unregister_usb_transport(usb_handle* usb);
+#endif
 
 /* Connect to a network address and register it as a device */
 void connect_device(const std::string& address, std::string* response);
@@ -454,9 +454,6 @@
                                atransport::ReconnectCallback reconnect, bool use_tls,
                                int* error = nullptr);
 
-// This should only be used for transports with connection_state == kCsNoPerm.
-void unregister_usb_transport(usb_handle* usb);
-
 bool check_header(apacket* p, atransport* t);
 
 void close_usb_devices(bool reset = false);
diff --git a/fastboot/Android.bp b/fastboot/Android.bp
index a757d56..884856d 100644
--- a/fastboot/Android.bp
+++ b/fastboot/Android.bp
@@ -115,6 +115,7 @@
         "device/fastboot_device.cpp",
         "device/flashing.cpp",
         "device/main.cpp",
+        "device/usb.cpp",
         "device/usb_client.cpp",
         "device/utility.cpp",
         "device/variables.cpp",
@@ -125,7 +126,6 @@
         "android.hardware.boot@1.1",
         "android.hardware.fastboot@1.0",
         "android.hardware.health@2.0",
-        "libadbd",
         "libasyncio",
         "libbase",
         "libbootloader_message",
diff --git a/adb/daemon/usb_legacy.cpp b/fastboot/device/usb.cpp
similarity index 70%
rename from adb/daemon/usb_legacy.cpp
rename to fastboot/device/usb.cpp
index fe80e7d..4bee7b2 100644
--- a/adb/daemon/usb_legacy.cpp
+++ b/fastboot/device/usb.cpp
@@ -14,9 +14,7 @@
  * limitations under the License.
  */
 
-#define TRACE_TAG USB
-
-#include "sysdeps.h"
+#include "usb.h"
 
 #include <dirent.h>
 #include <errno.h>
@@ -41,12 +39,9 @@
 #include <android-base/logging.h>
 #include <android-base/properties.h>
 
-#include "adb.h"
-#include "adbd/usb.h"
-#include "transport.h"
-
 using namespace std::chrono_literals;
 
+#define D(...)
 #define MAX_PACKET_SIZE_FS 64
 #define MAX_PACKET_SIZE_HS 512
 #define MAX_PACKET_SIZE_SS 1024
@@ -56,8 +51,6 @@
 // Number of buffers needed to fit MAX_PAYLOAD, with an extra for ZLPs.
 #define USB_FFS_NUM_BUFS ((4 * MAX_PAYLOAD / USB_FFS_BULK_SIZE) + 1)
 
-static unique_fd& dummy_fd = *new unique_fd();
-
 static void aio_block_init(aio_block* aiob, unsigned num_bufs) {
     aiob->iocb.resize(num_bufs);
     aiob->iocbs.resize(num_bufs);
@@ -82,46 +75,6 @@
     }
 }
 
-static bool init_functionfs(struct usb_handle* h) {
-    LOG(INFO) << "initializing functionfs";
-    if (!open_functionfs(&h->control, &h->bulk_out, &h->bulk_in)) {
-        return false;
-    }
-
-    h->read_aiob.fd = h->bulk_out.get();
-    h->write_aiob.fd = h->bulk_in.get();
-    h->reads_zero_packets = true;
-    return true;
-}
-
-static void usb_legacy_ffs_open_thread(usb_handle* usb) {
-    adb_thread_setname("usb legacy ffs open");
-
-    while (true) {
-        // wait until the USB device needs opening
-        std::unique_lock<std::mutex> lock(usb->lock);
-        while (!usb->open_new_connection) {
-            usb->notify.wait(lock);
-        }
-        usb->open_new_connection = false;
-        lock.unlock();
-
-        while (true) {
-            if (init_functionfs(usb)) {
-                LOG(INFO) << "functionfs successfully initialized";
-                break;
-            }
-            std::this_thread::sleep_for(1s);
-        }
-
-        LOG(INFO) << "registering usb transport";
-        register_usb_transport(usb, nullptr, nullptr, 1);
-    }
-
-    // never gets here
-    abort();
-}
-
 static int usb_ffs_write(usb_handle* h, const void* data, int len) {
     D("about to write (fd=%d, len=%d)", h->bulk_in.get(), len);
 
@@ -129,7 +82,7 @@
     int orig_len = len;
     while (len > 0) {
         int write_len = std::min(USB_FFS_BULK_SIZE, len);
-        int n = adb_write(h->bulk_in, buf, write_len);
+        int n = write(h->bulk_in, buf, write_len);
         if (n < 0) {
             D("ERROR: fd = %d, n = %d: %s", h->bulk_in.get(), n, strerror(errno));
             return -1;
@@ -150,7 +103,7 @@
     unsigned count = 0;
     while (len > 0) {
         int read_len = std::min(USB_FFS_BULK_SIZE, len);
-        int n = adb_read(h->bulk_out, buf, read_len);
+        int n = read(h->bulk_out, buf, read_len);
         if (n < 0) {
             D("ERROR: fd = %d, n = %d: %s", h->bulk_out.get(), n, strerror(errno));
             return -1;
@@ -232,7 +185,7 @@
     }
 }
 
-static int usb_ffs_aio_read(usb_handle* h, void* data, int len, bool allow_partial) {
+static int usb_ffs_aio_read(usb_handle* h, void* data, int len, bool /* allow_partial */) {
     return usb_ffs_do_aio(h, data, len, true);
 }
 
@@ -240,32 +193,9 @@
     return usb_ffs_do_aio(h, data, len, false);
 }
 
-static void usb_ffs_kick(usb_handle* h) {
-    int err;
-
-    err = ioctl(h->bulk_in.get(), FUNCTIONFS_CLEAR_HALT);
-    if (err < 0) {
-        D("[ kick: source (fd=%d) clear halt failed (%d) ]", h->bulk_in.get(), errno);
-    }
-
-    err = ioctl(h->bulk_out.get(), FUNCTIONFS_CLEAR_HALT);
-    if (err < 0) {
-        D("[ kick: sink (fd=%d) clear halt failed (%d) ]", h->bulk_out.get(), errno);
-    }
-
-    // don't close ep0 here, since we may not need to reinitialize it with
-    // the same descriptors again. if however ep1/ep2 fail to re-open in
-    // init_functionfs, only then would we close and open ep0 again.
-    // Ditto the comment in usb_adb_kick.
-    h->kicked = true;
-    TEMP_FAILURE_RETRY(dup2(dummy_fd.get(), h->bulk_out.get()));
-    TEMP_FAILURE_RETRY(dup2(dummy_fd.get(), h->bulk_in.get()));
-}
-
 static void usb_ffs_close(usb_handle* h) {
     LOG(INFO) << "closing functionfs transport";
 
-    h->kicked = false;
     h->bulk_out.reset();
     h->bulk_in.reset();
 
@@ -291,37 +221,6 @@
         aio_block_init(&h->write_aiob, num_bufs);
     }
     h->io_size = io_size;
-    h->kick = usb_ffs_kick;
     h->close = usb_ffs_close;
     return h;
 }
-
-void usb_init_legacy() {
-    D("[ usb_init - using legacy FunctionFS ]");
-    dummy_fd.reset(adb_open("/dev/null", O_WRONLY | O_CLOEXEC));
-    CHECK_NE(-1, dummy_fd.get());
-
-    std::thread(usb_legacy_ffs_open_thread, create_usb_handle(USB_FFS_NUM_BUFS, USB_FFS_BULK_SIZE))
-            .detach();
-}
-
-int usb_write(usb_handle* h, const void* data, int len) {
-    return h->write(h, data, len);
-}
-
-int usb_read(usb_handle* h, void* data, int len) {
-    return h->read(h, data, len, false /* allow_partial */);
-}
-
-int usb_close(usb_handle* h) {
-    h->close(h);
-    return 0;
-}
-
-void usb_reset(usb_handle* h) {
-    usb_close(h);
-}
-
-void usb_kick(usb_handle* h) {
-    h->kick(h);
-}
diff --git a/adb/daemon/include/adbd/usb.h b/fastboot/device/usb.h
similarity index 84%
rename from adb/daemon/include/adbd/usb.h
rename to fastboot/device/usb.h
index 2204246..6c3f542 100644
--- a/adb/daemon/include/adbd/usb.h
+++ b/fastboot/device/usb.h
@@ -36,17 +36,14 @@
 };
 
 struct usb_handle {
-    usb_handle() : kicked(false) {
-    }
+    usb_handle() {}
 
     std::condition_variable notify;
     std::mutex lock;
-    std::atomic<bool> kicked;
     bool open_new_connection = true;
 
     int (*write)(usb_handle* h, const void* data, int len);
     int (*read)(usb_handle* h, void* data, int len, bool allow_partial);
-    void (*kick)(usb_handle* h);
     void (*close)(usb_handle* h);
 
     // FunctionFS
@@ -63,6 +60,4 @@
     size_t io_size;
 };
 
-usb_handle *create_usb_handle(unsigned num_bufs, unsigned io_size);
-bool open_functionfs(android::base::unique_fd* control, android::base::unique_fd* bulk_out,
-                     android::base::unique_fd* bulk_in);
+usb_handle* create_usb_handle(unsigned num_bufs, unsigned io_size);
diff --git a/fastboot/device/usb_client.h b/fastboot/device/usb_client.h
index e6a1a8b..e702a0d 100644
--- a/fastboot/device/usb_client.h
+++ b/fastboot/device/usb_client.h
@@ -17,7 +17,7 @@
 
 #include <memory>
 
-#include <adbd/usb.h>
+#include "usb.h"
 
 #include "transport.h"
 
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 5ebffab..adfdb7b 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -825,6 +825,11 @@
     start zygote
     start zygote_secondary
 
+on boot && property:ro.config.low_ram=true
+    # Tweak background writeout
+    write /proc/sys/vm/dirty_expire_centisecs 200
+    write /proc/sys/vm/dirty_background_ratio  5
+
 on boot
     # basic network init
     ifup lo
@@ -846,11 +851,7 @@
     chown root system /sys/block/zram0/writeback
     chmod 0664 /sys/block/zram0/writeback
 
-    # Tweak background writeout
-    write /proc/sys/vm/dirty_expire_centisecs 200
-    write /proc/sys/vm/dirty_background_ratio  5
-
-    # F2FS tuning. Set cp_interval larger than dirty_expire_centisecs
+    # F2FS tuning. Set cp_interval larger than dirty_expire_centisecs, 30 secs,
     # to avoid power consumption when system becomes mostly idle. Be careful
     # to make it too large, since it may bring userdata loss, if they
     # are not aware of using fsync()/sync() to prepare sudden power-cut.