diff --git a/app/src/main/java/com/topjohnwu/magisk/view/dialogs/InstallMethodDialog.kt b/app/src/main/java/com/topjohnwu/magisk/view/dialogs/InstallMethodDialog.kt
index 1cc63c6d3..2831d0386 100644
--- a/app/src/main/java/com/topjohnwu/magisk/view/dialogs/InstallMethodDialog.kt
+++ b/app/src/main/java/com/topjohnwu/magisk/view/dialogs/InstallMethodDialog.kt
@@ -15,9 +15,11 @@ import com.topjohnwu.magisk.utils.Utils
 import com.topjohnwu.magisk.view.ProgressNotification
 import com.topjohnwu.magisk.view.SnackbarMaker
 import com.topjohnwu.net.Networking
+import com.topjohnwu.superuser.ShellUtils
 import java.io.File
 
-internal class InstallMethodDialog(activity: MagiskActivity<*, *>, options: List<String>) : AlertDialog.Builder(activity) {
+internal class InstallMethodDialog(activity: MagiskActivity<*, *>, options: List<String>) :
+    AlertDialog.Builder(activity) {
 
     init {
         setTitle(R.string.select_method)
@@ -27,7 +29,7 @@ internal class InstallMethodDialog(activity: MagiskActivity<*, *>, options: List
                 1 -> patchBoot(activity)
                 2 -> {
                     val intent = Intent(activity, ClassMap[FlashActivity::class.java])
-                            .putExtra(Const.Key.FLASH_ACTION, Const.Value.FLASH_MAGISK)
+                        .putExtra(Const.Key.FLASH_ACTION, Const.Value.FLASH_MAGISK)
                     activity.startActivity(intent)
                 }
                 3 -> installInactiveSlot(activity)
@@ -40,13 +42,13 @@ internal class InstallMethodDialog(activity: MagiskActivity<*, *>, options: List
             onSuccess {
                 Utils.toast(R.string.patch_file_msg, Toast.LENGTH_LONG)
                 val intent = Intent(Intent.ACTION_GET_CONTENT)
-                        .setType("*/*")
-                        .addCategory(Intent.CATEGORY_OPENABLE)
+                    .setType("*/*")
+                    .addCategory(Intent.CATEGORY_OPENABLE)
                 activity.startActivityForResult(intent, Const.ID.SELECT_BOOT) { resultCode, data ->
                     if (resultCode == Activity.RESULT_OK && data != null) {
                         val i = Intent(this, ClassMap[FlashActivity::class.java])
-                                .setData(data.data)
-                                .putExtra(Const.Key.FLASH_ACTION, Const.Value.PATCH_FILE)
+                            .setData(data.data)
+                            .putExtra(Const.Key.FLASH_ACTION, Const.Value.PATCH_FILE)
                         startActivity(i)
                     }
                 }
@@ -60,31 +62,45 @@ internal class InstallMethodDialog(activity: MagiskActivity<*, *>, options: List
                 val filename = "Magisk-v${Info.remote.magisk.version}" +
                         "(${Info.remote.magisk.versionCode}).zip"
                 val zip = File(Const.EXTERNAL_PATH, filename)
-                val progress = ProgressNotification(filename)
-                Networking.get(Info.remote.magisk.link)
+                val cachedZip = File(activity.cacheDir, "magisk.zip")
+
+                fun onSuccess() {
+                    SnackbarMaker.make(
+                        activity,
+                        activity.getString(R.string.internal_storage, "/Download/$filename"),
+                        Snackbar.LENGTH_LONG
+                    ).show()
+                }
+
+                if (ShellUtils.checkSum("MD5", cachedZip, Info.remote.magisk.hash)) {
+                    cachedZip.copyTo(zip, true)
+                    onSuccess()
+                } else {
+                    val progress = ProgressNotification(filename)
+                    Networking.get(Info.remote.magisk.link)
                         .setDownloadProgressListener(progress)
                         .setErrorHandler { _, _ -> progress.dlFail() }
                         .getAsFile(zip) {
                             progress.dlDone()
-                            SnackbarMaker.make(activity,
-                                    activity.getString(R.string.internal_storage, "/Download/$filename"),
-                                    Snackbar.LENGTH_LONG).show()
+                            onSuccess()
                         }
+                }
+
             }
         }
     }
 
     private fun installInactiveSlot(activity: MagiskActivity<*, *>) {
         CustomAlertDialog(activity)
-                .setTitle(R.string.warning)
-                .setMessage(R.string.install_inactive_slot_msg)
-                .setCancelable(true)
-                .setPositiveButton(R.string.yes) { _, _ ->
-                    val intent = Intent(activity, ClassMap[FlashActivity::class.java])
-                            .putExtra(Const.Key.FLASH_ACTION, Const.Value.FLASH_INACTIVE_SLOT)
-                    activity.startActivity(intent)
-                }
-                .setNegativeButton(R.string.no_thanks, null)
-                .show()
+            .setTitle(R.string.warning)
+            .setMessage(R.string.install_inactive_slot_msg)
+            .setCancelable(true)
+            .setPositiveButton(R.string.yes) { _, _ ->
+                val intent = Intent(activity, ClassMap[FlashActivity::class.java])
+                    .putExtra(Const.Key.FLASH_ACTION, Const.Value.FLASH_INACTIVE_SLOT)
+                activity.startActivity(intent)
+            }
+            .setNegativeButton(R.string.no_thanks, null)
+            .show()
     }
 }