diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index bd57d1d8b..cc9294829 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -98,7 +98,7 @@ dependencies {
     implementation("io.noties.markwon:image:${vMarkwon}")
     implementation("com.caverock:androidsvg:1.4")
 
-    val vLibsu = "2.5.1"
+    val vLibsu = "2.5.2"
     implementation("com.github.topjohnwu.libsu:core:${vLibsu}")
     implementation("com.github.topjohnwu.libsu:io:${vLibsu}")
 
diff --git a/app/src/main/java/com/topjohnwu/magisk/core/App.kt b/app/src/main/java/com/topjohnwu/magisk/core/App.kt
index 4adab55bd..9ce1ab5f1 100644
--- a/app/src/main/java/com/topjohnwu/magisk/core/App.kt
+++ b/app/src/main/java/com/topjohnwu/magisk/core/App.kt
@@ -12,6 +12,7 @@ import com.topjohnwu.magisk.BuildConfig
 import com.topjohnwu.magisk.DynAPK
 import com.topjohnwu.magisk.FileProvider
 import com.topjohnwu.magisk.core.su.SuCallbackHandler
+import com.topjohnwu.magisk.core.utils.IODispatcherExecutor
 import com.topjohnwu.magisk.core.utils.RootInit
 import com.topjohnwu.magisk.core.utils.updateConfig
 import com.topjohnwu.magisk.di.koinModules
@@ -31,8 +32,9 @@ open class App() : Application() {
     init {
         AppCompatDelegate.setCompatVectorFromResourcesEnabled(true)
         Shell.Config.setFlags(Shell.FLAG_MOUNT_MASTER)
-        Shell.Config.addInitializers(RootInit::class.java)
+        Shell.Config.setInitializers(RootInit::class.java)
         Shell.Config.setTimeout(2)
+        Shell.EXECUTOR = IODispatcherExecutor()
         FileProvider.callHandler = SuCallbackHandler
 
         // Always log full stack trace with Timber
diff --git a/app/src/main/java/com/topjohnwu/magisk/core/download/RemoteFileService.kt b/app/src/main/java/com/topjohnwu/magisk/core/download/RemoteFileService.kt
index e68c217c8..208aa5b82 100644
--- a/app/src/main/java/com/topjohnwu/magisk/core/download/RemoteFileService.kt
+++ b/app/src/main/java/com/topjohnwu/magisk/core/download/RemoteFileService.kt
@@ -9,11 +9,11 @@ import com.topjohnwu.magisk.core.ForegroundTracker
 import com.topjohnwu.magisk.core.utils.ProgressInputStream
 import com.topjohnwu.magisk.core.view.Notifications
 import com.topjohnwu.magisk.data.network.GithubRawServices
+import com.topjohnwu.magisk.ktx.checkSum
 import com.topjohnwu.magisk.ktx.writeTo
 import com.topjohnwu.magisk.model.entity.internal.DownloadSubject
 import com.topjohnwu.magisk.model.entity.internal.DownloadSubject.Magisk
 import com.topjohnwu.magisk.model.entity.internal.DownloadSubject.Module
-import com.topjohnwu.superuser.ShellUtils
 import kotlinx.coroutines.launch
 import okhttp3.ResponseBody
 import org.koin.android.ext.android.inject
@@ -48,7 +48,7 @@ abstract class RemoteFileService : NotificationService() {
     private suspend fun start(subject: DownloadSubject) {
         if (subject !is Magisk ||
             !subject.file.exists() ||
-            !ShellUtils.checkSum("MD5", subject.file, subject.magisk.md5)) {
+            !subject.file.checkSum("MD5", subject.magisk.md5)) {
             val stream = service.fetchFile(subject.url).toProgressStream(subject)
             when (subject) {
                 is Module ->
diff --git a/app/src/main/java/com/topjohnwu/magisk/core/utils/IODispatcherExecutor.kt b/app/src/main/java/com/topjohnwu/magisk/core/utils/IODispatcherExecutor.kt
new file mode 100644
index 000000000..c12f037d3
--- /dev/null
+++ b/app/src/main/java/com/topjohnwu/magisk/core/utils/IODispatcherExecutor.kt
@@ -0,0 +1,36 @@
+package com.topjohnwu.magisk.core.utils
+
+import kotlinx.coroutines.*
+import java.util.concurrent.*
+
+class IODispatcherExecutor : AbstractExecutorService() {
+
+    private val job = SupervisorJob().apply { invokeOnCompletion { future.run() } }
+    private val scope = CoroutineScope(job + Dispatchers.IO)
+    private val future = FutureTask(Callable { true })
+
+    override fun execute(command: Runnable) {
+        scope.launch {
+            command.run()
+        }
+    }
+
+    override fun shutdown() = job.cancel()
+
+    override fun shutdownNow(): List<Runnable> {
+        job.cancel()
+        return emptyList()
+    }
+
+    override fun isShutdown() = job.isCancelled
+
+    override fun isTerminated() = job.isCancelled && job.isCompleted
+
+    override fun awaitTermination(timeout: Long, unit: TimeUnit): Boolean {
+        return try {
+            future.get(timeout, unit)
+        } catch (e: TimeoutException) {
+            false
+        }
+    }
+}
diff --git a/app/src/main/java/com/topjohnwu/magisk/ktx/XJava.kt b/app/src/main/java/com/topjohnwu/magisk/ktx/XJava.kt
index 8c816b58e..fbbece90b 100644
--- a/app/src/main/java/com/topjohnwu/magisk/ktx/XJava.kt
+++ b/app/src/main/java/com/topjohnwu/magisk/ktx/XJava.kt
@@ -8,10 +8,12 @@ import java.io.InputStream
 import java.io.OutputStream
 import java.lang.reflect.Field
 import java.lang.reflect.Method
+import java.security.MessageDigest
 import java.text.SimpleDateFormat
 import java.util.*
 import java.util.zip.ZipEntry
 import java.util.zip.ZipInputStream
+import kotlin.experimental.and
 
 fun ZipInputStream.forEach(callback: (ZipEntry) -> Unit) {
     var entry: ZipEntry? = nextEntry
@@ -22,7 +24,24 @@ fun ZipInputStream.forEach(callback: (ZipEntry) -> Unit) {
 }
 
 fun InputStream.writeTo(file: File) =
-        withStreams(this, file.outputStream()) { reader, writer -> reader.copyTo(writer) }
+    withStreams(this, file.outputStream()) { reader, writer -> reader.copyTo(writer) }
+
+fun File.checkSum(alg: String, reference: String) = runCatching {
+    inputStream().use {
+        val digest = MessageDigest.getInstance(alg)
+        it.copyTo(object : OutputStream() {
+            override fun write(b: Int) {
+                digest.update(b.toByte())
+            }
+            override fun write(b: ByteArray, off: Int, len: Int) {
+                digest.update(b, off, len)
+            }
+        })
+        val sb = StringBuilder()
+        digest.digest().forEach { b -> sb.append("%02x".format(b and 0xff.toByte())) }
+        sb.toString() == reference
+    }
+}.getOrElse { false }
 
 inline fun <In : InputStream, Out : OutputStream> withStreams(
     inStream: In,