diff --git a/build.gradle.kts b/build.gradle.kts
index 29d908f..4beddc7 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -29,7 +29,7 @@ val verCode by extra(gitCommitCount)
 val commitHash by extra(gitCommitHash)
 val abiList by extra(listOf("arm64-v8a", "x86_64"))
 
-val androidMinSdkVersion by extra(26)
+val androidMinSdkVersion by extra(31)
 val androidTargetSdkVersion by extra(34)
 val androidCompileSdkVersion by extra(34)
 val androidBuildToolsVersion by extra("34.0.0")
diff --git a/module/build.gradle.kts b/module/build.gradle.kts
index e40d1be..12d3bac 100644
--- a/module/build.gradle.kts
+++ b/module/build.gradle.kts
@@ -14,6 +14,12 @@ val verName: String by rootProject.extra
 val commitHash: String by rootProject.extra
 val abiList: List<String> by rootProject.extra
 
+val releaseFlags = arrayOf(
+    "-Oz", "-flto",
+    "-Wno-unused", "-Wno-unused-parameter",
+    "-Wl,--exclude-libs,ALL", "-Wl,--gc-sections",
+)
+
 android {
     defaultConfig {
         ndk {
@@ -34,6 +40,14 @@ android {
             path("src/main/cpp/CMakeLists.txt")
         }
     }
+    buildTypes {
+        release {
+            externalNativeBuild.cmake {
+                cFlags += releaseFlags
+                cppFlags += releaseFlags
+            }
+        }
+    }
 }
 
 androidComponents.onVariants { variant ->
diff --git a/module/src/main/cpp/CMakeLists.txt b/module/src/main/cpp/CMakeLists.txt
index ee13a33..d7c8dc6 100644
--- a/module/src/main/cpp/CMakeLists.txt
+++ b/module/src/main/cpp/CMakeLists.txt
@@ -3,7 +3,6 @@ project(sample)
 
 set(LINKER_FLAGS "-ffixed-x18 -Wl,--hash-style=both")
 
-# TODO: set visibility only for our libs (-fvisibility=hidden -fvisibility-inlines-hidden)
 set(CXX_FLAGS "${CXX_FLAGS} -fno-exceptions -fno-rtti")
 
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CXX_FLAGS}")
@@ -37,6 +36,8 @@ target_link_libraries(binder utils)
 
 add_executable(libinject.so inject/main.cpp inject/utils.cpp)
 target_link_libraries(libinject.so lspmparser my_logging)
+target_compile_options(libinject.so PRIVATE -fvisibility=hidden -fvisibility-inlines-hidden)
 
 add_library(${MODULE_NAME} SHARED binder_interceptor.cpp)
 target_link_libraries(${MODULE_NAME} log binder utils dobby elf_util my_logging)
+target_compile_options(${MODULE_NAME} PRIVATE -fvisibility=hidden -fvisibility-inlines-hidden)
diff --git a/module/src/main/cpp/inject/main.cpp b/module/src/main/cpp/inject/main.cpp
index 0fe6c7d..7da8aeb 100644
--- a/module/src/main/cpp/inject/main.cpp
+++ b/module/src/main/cpp/inject/main.cpp
@@ -290,7 +290,9 @@ bool inject_library(int pid, const char *lib_path, const char* entry_name) {
 }
 
 int main(int argc, char **argv) {
+#ifndef NDEBUG
     logging::setPrintEnabled(true);
+#endif
     auto pid = strtol(argv[1], nullptr, 0);
     char buf[4096];
     realpath(argv[2], buf);
diff --git a/service/build.gradle.kts b/service/build.gradle.kts
index 9a8e041..eb92a16 100644
--- a/service/build.gradle.kts
+++ b/service/build.gradle.kts
@@ -13,7 +13,8 @@ android {
 
     buildTypes {
         release {
-            isMinifyEnabled = false
+            isMinifyEnabled = true
+            isShrinkResources = true
             proguardFiles(
                 getDefaultProguardFile("proguard-android-optimize.txt"),
                 "proguard-rules.pro"
@@ -23,6 +24,11 @@ android {
     kotlinOptions {
         jvmTarget = "17"
     }
+    buildTypes {
+        release {
+            signingConfig = signingConfigs["debug"]
+        }
+    }
 }
 
 dependencies {
diff --git a/service/proguard-rules.pro b/service/proguard-rules.pro
index 481bb43..082bf02 100644
--- a/service/proguard-rules.pro
+++ b/service/proguard-rules.pro
@@ -18,4 +18,11 @@
 
 # If you keep the line number information, uncomment this to
 # hide the original source file name.
-#-renamesourcefileattribute SourceFile
\ No newline at end of file
+#-renamesourcefileattribute SourceFile
+-keepclasseswithmembers class io.github.a13e300.tricky_store.MainKt {
+    public static void main(java.lang.String[]);
+}
+
+-assumenosideeffects class io.github.a13e300.tricky_store.Logger {
+    public static void d(java.lang.String);
+}
diff --git a/service/src/main/java/io/github/a13e300/tricky_store/Logger.java b/service/src/main/java/io/github/a13e300/tricky_store/Logger.java
index bebd1b3..43bc0ac 100644
--- a/service/src/main/java/io/github/a13e300/tricky_store/Logger.java
+++ b/service/src/main/java/io/github/a13e300/tricky_store/Logger.java
@@ -16,4 +16,8 @@ public class Logger {
         Log.e(TAG, msg, t);
     }
 
+    public static void i(String msg) {
+        Log.i(TAG, msg);
+    }
+
 }
diff --git a/service/src/main/java/io/github/a13e300/tricky_store/Main.kt b/service/src/main/java/io/github/a13e300/tricky_store/Main.kt
index c610843..1e19458 100644
--- a/service/src/main/java/io/github/a13e300/tricky_store/Main.kt
+++ b/service/src/main/java/io/github/a13e300/tricky_store/Main.kt
@@ -119,20 +119,6 @@ fun registerBinderInterceptor(backdoor: IBinder, target: IBinder, interceptor: B
 val targetPackages = mutableSetOf<String>()
 val DEFAULT_TARGET_PACKAGES = listOf("com.google.android.gms", "icu.nullptr.nativetest", "io.github.vvb2060.mahoshojo", "io.github.vvb2060.keyattestation")
 
-const val TAG = "TrickyStore"
-
-fun logD(msg: String) {
-    Log.d(TAG, msg)
-}
-
-fun logE(msg: String, t: Throwable? = null) {
-    if (t == null) {
-        Log.e(TAG, msg)
-    } else {
-        Log.e(TAG, msg, t)
-    }
-}
-
 var iPm: IPackageManager? = null
 
 fun getPm(): IPackageManager? {
@@ -163,7 +149,7 @@ const val TARGET_FILE = "target.txt"
 const val KEYBOX_FILE = "keybox.xml"
 
 class ConfigObserver : FileObserver(CONFIG_PATH, CLOSE_WRITE) {
-    val root = File(CONFIG_PATH)
+    private val root = File(CONFIG_PATH)
     override fun onEvent(event: Int, path: String?) {
         path ?: return
         if (event == CLOSE_WRITE) {
@@ -180,7 +166,7 @@ class ConfigObserver : FileObserver(CONFIG_PATH, CLOSE_WRITE) {
 fun tryRunKeystoreInterceptor(): Boolean {
     val b = ServiceManager.getService("android.system.keystore2.IKeystoreService/default") ?: return false
     b.linkToDeath({
-        logD("keystore exit, daemon exit")
+        Logger.d("keystore exit, daemon exit")
         exitProcess(0)
     }, 0)
     val bd = getBinderBackdoor(b) ?: return true
@@ -195,11 +181,11 @@ fun tryRunKeystoreInterceptor(): Boolean {
             data: Parcel
         ): Result {
             if (code == targetTransaction) {
-                logD("intercept pre  $target uid=$callingUid pid=$callingPid dataSz=${data.dataSize()}")
+                Logger.d("intercept pre  $target uid=$callingUid pid=$callingPid dataSz=${data.dataSize()}")
                 kotlin.runCatching {
                     val ps = getPm()?.getPackagesForUid(callingUid)
                     if (ps?.any { it in targetPackages } == true) return Continue
-                }.onFailure { logE("failed to get packages", it) }
+                }.onFailure { Logger.e("failed to get packages", it) }
             }
             return Skip
         }
@@ -216,7 +202,7 @@ fun tryRunKeystoreInterceptor(): Boolean {
         ): Result {
             if (code != targetTransaction || reply == null) return Skip
             val p = Parcel.obtain()
-            logD("intercept post $target uid=$callingUid pid=$callingPid dataSz=${data.dataSize()} replySz=${reply.dataSize()}")
+            Logger.d("intercept post $target uid=$callingUid pid=$callingPid dataSz=${data.dataSize()} replySz=${reply.dataSize()}")
             try {
                 reply.readException()
                 val response = reply.readTypedObject(KeyEntryResponse.CREATOR)
@@ -227,7 +213,7 @@ fun tryRunKeystoreInterceptor(): Boolean {
                 p.writeTypedObject(response, 0)
                 return OverrideReply(0, p)
             } catch (t: Throwable) {
-                logE("failed to hack certificate chain!", t)
+                Logger.e("failed to hack certificate chain!", t)
                 p.recycle()
             }
             return Skip
@@ -255,7 +241,7 @@ fun tryRunKeystoreInterceptor(): Boolean {
     }
 }
 
-fun main() {
+fun main(args: Array<String>) {
     while (true) {
         Thread.sleep(1000)
         // true -> can inject, false -> service not found, loop -> running
@@ -271,7 +257,7 @@ fun main() {
         // logD(p.inputStream.readBytes().decodeToString())
         // logD(p.errorStream.readBytes().decodeToString())
         if (p.waitFor() != 0) {
-            logE("failed to inject! daemon exit")
+            Logger.e("failed to inject! daemon exit")
             exitProcess(1)
         }
     }