diff --git a/Android.mk b/Android.mk
index 04b1625..7e34c10 100644
--- a/Android.mk
+++ b/Android.mk
@@ -94,7 +94,7 @@
 endif
 
 LOCAL_CFLAGS += -DRECOVERY_API_VERSION=$(RECOVERY_API_VERSION)
-LOCAL_CFLAGS += -Wall -Wno-unused-parameter -Werror
+LOCAL_CFLAGS += -Wall -Werror
 
 ifneq ($(TARGET_RECOVERY_UI_MARGIN_HEIGHT),)
 LOCAL_CFLAGS += -DRECOVERY_UI_MARGIN_HEIGHT=$(TARGET_RECOVERY_UI_MARGIN_HEIGHT)
@@ -173,9 +173,7 @@
     libcutils \
     libutils \
     liblog \
-    libselinux \
-    libm \
-    libc
+    libselinux
 
 LOCAL_HAL_STATIC_LIBRARIES := libhealthd
 
diff --git a/applypatch/Makefile b/applypatch/Makefile
deleted file mode 100644
index fb49843..0000000
--- a/applypatch/Makefile
+++ /dev/null
@@ -1,33 +0,0 @@
-# Copyright (C) 2016 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.
-
-# This file is for building imgdiff in Chrome OS.
-
-CPPFLAGS += -iquote.. -Iinclude
-CXXFLAGS += -std=c++11 -O3 -Wall -Werror
-LDLIBS += -lbz2 -lz
-
-.PHONY: all clean
-
-all: imgdiff libimgpatch.a
-
-clean:
-	rm -f *.o imgdiff libimgpatch.a
-
-imgdiff: imgdiff.o bsdiff.o utils.o
-	$(CXX) $(CPPFLAGS) $(CXXFLAGS) $(LDLIBS) -o $@ $^
-
-libimgpatch.a utils.o: CXXFLAGS += -fPIC
-libimgpatch.a: imgpatch.o bspatch.o utils.o
-	${AR} rcs $@ $^
diff --git a/applypatch/libimgpatch.pc b/applypatch/libimgpatch.pc
deleted file mode 100644
index e500293..0000000
--- a/applypatch/libimgpatch.pc
+++ /dev/null
@@ -1,6 +0,0 @@
-# This file is for libimgpatch in Chrome OS.
-
-Name: libimgpatch
-Description: Apply imgdiff patch
-Version: 0.0.1
-Libs: -limgpatch -lbz2 -lz
diff --git a/boot_control/Android.mk b/boot_control/Android.mk
index 27e3d97..9814d71 100644
--- a/boot_control/Android.mk
+++ b/boot_control/Android.mk
@@ -24,8 +24,7 @@
   -D_FILE_OFFSET_BITS=64 \
   -Werror \
   -Wall \
-  -Wextra \
-  -Wno-unused-parameter
+  -Wextra
 LOCAL_SHARED_LIBRARIES := liblog
 LOCAL_STATIC_LIBRARIES := libbootloader_message libfs_mgr libbase
 LOCAL_POST_INSTALL_CMD := \
diff --git a/minadbd/Android.mk b/minadbd/Android.mk
index 8d86fd6..803171d 100644
--- a/minadbd/Android.mk
+++ b/minadbd/Android.mk
@@ -1,13 +1,26 @@
 # Copyright 2005 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.
 
 LOCAL_PATH:= $(call my-dir)
 
 minadbd_cflags := \
     -Wall -Werror \
-    -Wno-unused-parameter \
     -Wno-missing-field-initializers \
     -DADB_HOST=0 \
 
+# libadbd (static library)
+# ===============================
 include $(CLEAR_VARS)
 
 LOCAL_SRC_FILES := \
@@ -24,6 +37,8 @@
 
 include $(BUILD_STATIC_LIBRARY)
 
+# minadbd_test (native test)
+# ===============================
 include $(CLEAR_VARS)
 
 LOCAL_MODULE := minadbd_test
diff --git a/minadbd/minadbd_services.cpp b/minadbd/minadbd_services.cpp
index 61c06cc..9f0f1f8 100644
--- a/minadbd/minadbd_services.cpp
+++ b/minadbd/minadbd_services.cpp
@@ -58,20 +58,20 @@
     return s[0];
 }
 
-int service_to_fd(const char* name, const atransport* transport) {
-    int ret = -1;
+int service_to_fd(const char* name, const atransport* /* transport */) {
+  int ret = -1;
 
-    if (!strncmp(name, "sideload:", 9)) {
-        // this exit status causes recovery to print a special error
-        // message saying to use a newer adb (that supports
-        // sideload-host).
-        exit(3);
-    } else if (!strncmp(name, "sideload-host:", 14)) {
-        std::string arg(name + 14);
-        ret = create_service_thread(sideload_host_service, arg);
-    }
-    if (ret >= 0) {
-        close_on_exec(ret);
-    }
-    return ret;
+  if (!strncmp(name, "sideload:", 9)) {
+    // this exit status causes recovery to print a special error
+    // message saying to use a newer adb (that supports
+    // sideload-host).
+    exit(3);
+  } else if (!strncmp(name, "sideload-host:", 14)) {
+    std::string arg(name + 14);
+    ret = create_service_thread(sideload_host_service, arg);
+  }
+  if (ret >= 0) {
+    close_on_exec(ret);
+  }
+  return ret;
 }
diff --git a/minui/Android.mk b/minui/Android.mk
index 9a217a4..ae1552b 100644
--- a/minui/Android.mk
+++ b/minui/Android.mk
@@ -13,6 +13,9 @@
 # limitations under the License.
 
 LOCAL_PATH := $(call my-dir)
+
+# libminui (static library)
+# ===============================
 include $(CLEAR_VARS)
 
 LOCAL_SRC_FILES := \
@@ -66,6 +69,8 @@
 
 include $(BUILD_STATIC_LIBRARY)
 
+# libminui (shared library)
+# ===============================
 # Used by OEMs for factory test images.
 include $(CLEAR_VARS)
 LOCAL_MODULE := libminui
diff --git a/minui/events.cpp b/minui/events.cpp
index 24c2a82..2894c3b 100644
--- a/minui/events.cpp
+++ b/minui/events.cpp
@@ -15,6 +15,7 @@
  */
 
 #include <dirent.h>
+#include <errno.h>
 #include <fcntl.h>
 #include <linux/input.h>
 #include <stdio.h>
diff --git a/otafault/ota_io.cpp b/otafault/ota_io.cpp
index 1308973..63ef18e 100644
--- a/otafault/ota_io.cpp
+++ b/otafault/ota_io.cpp
@@ -26,6 +26,7 @@
 
 #include <map>
 #include <mutex>
+#include <string>
 
 #include <android-base/thread_annotations.h>
 
diff --git a/otautil/SysUtil.cpp b/otautil/SysUtil.cpp
index 0655c47..48336ad 100644
--- a/otautil/SysUtil.cpp
+++ b/otautil/SysUtil.cpp
@@ -16,6 +16,7 @@
 
 #include "otautil/SysUtil.h"
 
+#include <errno.h>  // TEMP_FAILURE_RETRY
 #include <fcntl.h>
 #include <stdint.h>  // SIZE_MAX
 #include <sys/mman.h>
diff --git a/recovery.cpp b/recovery.cpp
index 243ee4a..a899163 100644
--- a/recovery.cpp
+++ b/recovery.cpp
@@ -1214,9 +1214,8 @@
   }
 }
 
-static void
-print_property(const char *key, const char *name, void *cookie) {
-    printf("%s=%s\n", key, name);
+static void print_property(const char* key, const char* name, void* /* cookie */) {
+  printf("%s=%s\n", key, name);
 }
 
 static std::string load_locale_from_cache() {
@@ -1250,14 +1249,14 @@
 
 static constexpr char log_characters[] = "VDIWEF";
 
-void UiLogger(android::base::LogId id, android::base::LogSeverity severity,
-               const char* tag, const char* file, unsigned int line,
-               const char* message) {
-    if (severity >= android::base::ERROR && ui != nullptr) {
-        ui->Print("E:%s\n", message);
-    } else {
-        fprintf(stdout, "%c:%s\n", log_characters[severity], message);
-    }
+void UiLogger(android::base::LogId /* id */, android::base::LogSeverity severity,
+              const char* /* tag */, const char* /* file */, unsigned int /* line */,
+              const char* message) {
+  if (severity >= android::base::ERROR && ui != nullptr) {
+    ui->Print("E:%s\n", message);
+  } else {
+    fprintf(stdout, "%c:%s\n", log_characters[severity], message);
+  }
 }
 
 static bool is_battery_ok() {
diff --git a/stub_ui.h b/stub_ui.h
index 85dbcfd..1f6b29a 100644
--- a/stub_ui.h
+++ b/stub_ui.h
@@ -24,18 +24,18 @@
  public:
   StubRecoveryUI() = default;
 
-  void SetBackground(Icon icon) override {}
-  void SetSystemUpdateText(bool security_update) override {}
+  void SetBackground(Icon /* icon */) override {}
+  void SetSystemUpdateText(bool /* security_update */) override {}
 
   // progress indicator
-  void SetProgressType(ProgressType type) override {}
-  void ShowProgress(float portion, float seconds) override {}
-  void SetProgress(float fraction) override {}
+  void SetProgressType(ProgressType /* type */) override {}
+  void ShowProgress(float /* portion */, float /* seconds */) override {}
+  void SetProgress(float /* fraction */) override {}
 
-  void SetStage(int current, int max) override {}
+  void SetStage(int /* current */, int /* max */) override {}
 
   // text log
-  void ShowText(bool visible) override {}
+  void ShowText(bool /* visible */) override {}
   bool IsTextVisible() override {
     return false;
   }
@@ -50,12 +50,12 @@
     vprintf(fmt, ap);
     va_end(ap);
   }
-  void PrintOnScreenOnly(const char* fmt, ...) override {}
-  void ShowFile(const char* filename) override {}
+  void PrintOnScreenOnly(const char* /* fmt */, ...) override {}
+  void ShowFile(const char* /* filename */) override {}
 
   // menu display
-  void StartMenu(const char* const* headers, const char* const* items,
-                 int initial_selection) override {}
+  void StartMenu(const char* const* /* headers */, const char* const* /* items */,
+                 int /* initial_selection */) override {}
   int SelectMenu(int sel) override {
     return sel;
   }
diff --git a/updater/Android.mk b/updater/Android.mk
index 1218160..6f334ee 100644
--- a/updater/Android.mk
+++ b/updater/Android.mk
@@ -67,7 +67,6 @@
 
 LOCAL_CFLAGS := \
     -Wall \
-    -Wno-unused-parameter \
     -Werror
 
 LOCAL_EXPORT_C_INCLUDE_DIRS := \
@@ -93,7 +92,6 @@
 
 LOCAL_CFLAGS := \
     -Wall \
-    -Wno-unused-parameter \
     -Werror
 
 LOCAL_STATIC_LIBRARIES := \
diff --git a/vr_ui.cpp b/vr_ui.cpp
index 07cc9da..a58c99e 100644
--- a/vr_ui.cpp
+++ b/vr_ui.cpp
@@ -53,7 +53,7 @@
   return y + 4;
 }
 
-void VrRecoveryUI::DrawHighlightBar(int x, int y, int width, int height) const {
+void VrRecoveryUI::DrawHighlightBar(int /* x */, int y, int /* width */, int height) const {
   gr_fill(kMarginWidth + kStereoOffset, y, ScreenWidth() - kMarginWidth + kStereoOffset, y + height);
   gr_fill(ScreenWidth() + kMarginWidth - kStereoOffset, y,
           gr_fb_width() - kMarginWidth - kStereoOffset, y + height);
diff --git a/wear_ui.cpp b/wear_ui.cpp
index e2ee488..ca6b1b1 100644
--- a/wear_ui.cpp
+++ b/wear_ui.cpp
@@ -150,8 +150,7 @@
   gr_flip();
 }
 
-void WearRecoveryUI::SetStage(int current, int max) {
-}
+void WearRecoveryUI::SetStage(int /* current */, int /* max */) {}
 
 void WearRecoveryUI::StartMenu(const char* const* headers, const char* const* items,
                                int initial_selection) {