diff --git a/init/Android.bp b/init/Android.bp
index dd67d04..f91265e 100644
--- a/init/Android.bp
+++ b/init/Android.bp
@@ -178,7 +178,6 @@
         "update_metadata-protos",
     ],
     shared_libs: [
-        "libbacktrace",
         "libbase",
         "libbootloader_message",
         "libcrypto",
@@ -195,6 +194,7 @@
         "libprocessgroup",
         "libprocessgroup_setup",
         "libselinux",
+        "libunwindstack",
         "libutils",
         "libziparchive",
     ],
@@ -352,7 +352,6 @@
         "libgsi",
         "liblzma",
         "libunwindstack_no_dex",
-        "libbacktrace_no_dex",
         "libmodprobe",
         "libext2_uuid",
         "libprotobuf-cpp-lite",
diff --git a/init/init.cpp b/init/init.cpp
index 038f172..f8330bc 100644
--- a/init/init.cpp
+++ b/init/init.cpp
@@ -48,7 +48,6 @@
 #include <android-base/properties.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
-#include <backtrace/Backtrace.h>
 #include <fs_avb/fs_avb.h>
 #include <fs_mgr_vendor_overlay.h>
 #include <keyutils.h>
@@ -58,6 +57,7 @@
 #include <processgroup/processgroup.h>
 #include <processgroup/setup.h>
 #include <selinux/android.h>
+#include <unwindstack/AndroidUnwinder.h>
 
 #include "action_parser.h"
 #include "builtins.h"
@@ -253,12 +253,14 @@
 } shutdown_state;
 
 static void UnwindMainThreadStack() {
-    std::unique_ptr<Backtrace> backtrace(Backtrace::Create(BACKTRACE_CURRENT_PROCESS, 1));
-    if (!backtrace->Unwind(0)) {
-        LOG(ERROR) << __FUNCTION__ << "sys.powerctl: Failed to unwind callstack.";
+    unwindstack::AndroidLocalUnwinder unwinder;
+    unwindstack::AndroidUnwinderData data;
+    if (!unwinder.Unwind(data)) {
+        LOG(ERROR) << __FUNCTION__
+                   << "sys.powerctl: Failed to unwind callstack: " << data.GetErrorString();
     }
-    for (size_t i = 0; i < backtrace->NumFrames(); i++) {
-        LOG(ERROR) << "sys.powerctl: " << backtrace->FormatFrameData(i);
+    for (const auto& frame : data.frames) {
+        LOG(ERROR) << "sys.powerctl: " << unwinder.FormatFrame(frame);
     }
 }
 
diff --git a/init/init_test.cpp b/init/init_test.cpp
index 8550ec8..8c19d5f 100644
--- a/init/init_test.cpp
+++ b/init/init_test.cpp
@@ -156,6 +156,7 @@
 
     ServiceList service_list;
     TestInitText(init_script, test_function_map, commands, &service_list);
+    EXPECT_EQ(3, num_executed);
 }
 
 TEST(init, OverrideService) {
diff --git a/init/reboot_utils.cpp b/init/reboot_utils.cpp
index b3fa9fd..f8e1de0 100644
--- a/init/reboot_utils.cpp
+++ b/init/reboot_utils.cpp
@@ -26,8 +26,8 @@
 #include <android-base/logging.h>
 #include <android-base/properties.h>
 #include <android-base/strings.h>
-#include <backtrace/Backtrace.h>
 #include <cutils/android_reboot.h>
+#include <unwindstack/AndroidUnwinder.h>
 
 #include "capabilities.h"
 #include "reboot_utils.h"
@@ -157,13 +157,13 @@
 
     // In the parent, let's try to get a backtrace then shutdown.
     LOG(ERROR) << __FUNCTION__ << ": signal " << signal_number;
-    std::unique_ptr<Backtrace> backtrace(
-            Backtrace::Create(BACKTRACE_CURRENT_PROCESS, BACKTRACE_CURRENT_THREAD));
-    if (!backtrace->Unwind(0)) {
-        LOG(ERROR) << __FUNCTION__ << ": Failed to unwind callstack.";
+    unwindstack::AndroidLocalUnwinder unwinder;
+    unwindstack::AndroidUnwinderData data;
+    if (!unwinder.Unwind(data)) {
+        LOG(ERROR) << __FUNCTION__ << ": Failed to unwind callstack: " << data.GetErrorString();
     }
-    for (size_t i = 0; i < backtrace->NumFrames(); i++) {
-        LOG(ERROR) << backtrace->FormatFrameData(i);
+    for (const auto& frame : data.frames) {
+        LOG(ERROR) << unwinder.FormatFrame(frame);
     }
     if (init_fatal_panic) {
         LOG(ERROR) << __FUNCTION__ << ": Trigger crash";
diff --git a/libutils/Android.bp b/libutils/Android.bp
index 1b29285..f663671 100644
--- a/libutils/Android.bp
+++ b/libutils/Android.bp
@@ -44,14 +44,6 @@
     export_include_dirs: ["include"],
 
     target: {
-        android: {
-            header_libs: ["libbacktrace_headers"],
-            export_header_lib_headers: ["libbacktrace_headers"],
-        },
-        host_linux: {
-            header_libs: ["libbacktrace_headers"],
-            export_header_lib_headers: ["libbacktrace_headers"],
-        },
         linux_bionic: {
             enabled: true,
         },
@@ -196,7 +188,7 @@
 
     shared_libs: [
         "libutils",
-        "libbacktrace",
+        "libunwindstack",
     ],
 
     target: {
diff --git a/libutils/CallStack.cpp b/libutils/CallStack.cpp
index fe6f33d..f19ba6a 100644
--- a/libutils/CallStack.cpp
+++ b/libutils/CallStack.cpp
@@ -20,7 +20,7 @@
 #include <utils/Errors.h>
 #include <utils/Log.h>
 
-#include <backtrace/Backtrace.h>
+#include <unwindstack/AndroidUnwinder.h>
 
 #define CALLSTACK_WEAK  // Don't generate weak definitions.
 #include <utils/CallStack.h>
@@ -39,14 +39,25 @@
 }
 
 void CallStack::update(int32_t ignoreDepth, pid_t tid) {
+    if (ignoreDepth < 0) {
+        ignoreDepth = 0;
+    }
+
     mFrameLines.clear();
 
-    std::unique_ptr<Backtrace> backtrace(Backtrace::Create(BACKTRACE_CURRENT_PROCESS, tid));
-    if (!backtrace->Unwind(ignoreDepth)) {
-        ALOGW("%s: Failed to unwind callstack.", __FUNCTION__);
+    unwindstack::AndroidLocalUnwinder unwinder;
+    unwindstack::AndroidUnwinderData data;
+    std::optional<pid_t> tid_val;
+    if (tid != -1) {
+        *tid_val = tid;
     }
-    for (size_t i = 0; i < backtrace->NumFrames(); i++) {
-      mFrameLines.push_back(String8(backtrace->FormatFrameData(i).c_str()));
+    if (!unwinder.Unwind(tid_val, data)) {
+        ALOGW("%s: Failed to unwind callstack: %s", __FUNCTION__, data.GetErrorString().c_str());
+    }
+    for (size_t i = ignoreDepth; i < data.frames.size(); i++) {
+        auto& frame = data.frames[i];
+        frame.num -= ignoreDepth;
+        mFrameLines.push_back(String8(unwinder.FormatFrame(frame).c_str()));
     }
 }
 
diff --git a/libutils/include/utils/CallStack.h b/libutils/include/utils/CallStack.h
index 7a4a345..fe4d4f5 100644
--- a/libutils/include/utils/CallStack.h
+++ b/libutils/include/utils/CallStack.h
@@ -20,7 +20,6 @@
 #include <memory>
 
 #include <android/log.h>
-#include <backtrace/backtrace_constants.h>
 #include <utils/String8.h>
 #include <utils/Vector.h>
 
@@ -59,7 +58,7 @@
 
     // Immediately collect the stack traces for the specified thread.
     // The default is to dump the stack of the current call.
-    void update(int32_t ignoreDepth = 1, pid_t tid = BACKTRACE_CURRENT_THREAD);
+    void update(int32_t ignoreDepth = 1, pid_t tid = -1);
 
     // Dump a stack trace to the log using the supplied logtag.
     void log(const char* logtag,
diff --git a/libutils/include/utils/Thread.h b/libutils/include/utils/Thread.h
index fc67656..5cf6b47 100644
--- a/libutils/include/utils/Thread.h
+++ b/libutils/include/utils/Thread.h
@@ -42,7 +42,9 @@
 {
 public:
     // Create a Thread object, but doesn't create or start the associated
-    // thread. See the run() method.
+    // thread. See the run() method. This object must be used with RefBase/sp,
+    // like any other RefBase object, because they are conventionally promoted
+    // from bare pointers (Thread::run is particularly problematic here).
     explicit            Thread(bool canCallJava = true);
     virtual             ~Thread();
 
diff --git a/rootdir/init.rc b/rootdir/init.rc
index a255d17..dcaaa4b 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -101,22 +101,18 @@
     exec_start boringssl_self_test_apex64
 
 service boringssl_self_test32 /system/bin/boringssl_self_test32
-    setenv BORINGSSL_SELF_TEST_CREATE_FLAG true # Any nonempty value counts as true
     reboot_on_failure reboot,boringssl-self-check-failed
     stdio_to_kmsg
 
 service boringssl_self_test64 /system/bin/boringssl_self_test64
-    setenv BORINGSSL_SELF_TEST_CREATE_FLAG true # Any nonempty value counts as true
     reboot_on_failure reboot,boringssl-self-check-failed
     stdio_to_kmsg
 
 service boringssl_self_test_apex32 /apex/com.android.conscrypt/bin/boringssl_self_test32
-    setenv BORINGSSL_SELF_TEST_CREATE_FLAG true # Any nonempty value counts as true
     reboot_on_failure reboot,boringssl-self-check-failed
     stdio_to_kmsg
 
 service boringssl_self_test_apex64 /apex/com.android.conscrypt/bin/boringssl_self_test64
-    setenv BORINGSSL_SELF_TEST_CREATE_FLAG true # Any nonempty value counts as true
     reboot_on_failure reboot,boringssl-self-check-failed
     stdio_to_kmsg
 
@@ -1127,12 +1123,6 @@
     chown system system /sys/devices/system/cpu/cpufreq/interactive/io_is_busy
     chmod 0660 /sys/devices/system/cpu/cpufreq/interactive/io_is_busy
 
-    # Assume SMP uses shared cpufreq policy for all CPUs in the same cluster.
-    # Here is for initial cluster (cpu0...) which is not hot-plugged in most cases.
-    # The rest of hot-plugged clusters are covered by ueventd.rc.
-    chown system system /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
-    chmod 0664 /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
-
     chown system system /sys/class/leds/vibrator/trigger
     chown system system /sys/class/leds/vibrator/activate
     chown system system /sys/class/leds/vibrator/brightness