diff --git a/app/src/main/java/eu/depau/etchdroid/activities/ConfirmationActivity.kt b/app/src/main/java/eu/depau/etchdroid/activities/ConfirmationActivity.kt
index c22955d..4692d81 100644
--- a/app/src/main/java/eu/depau/etchdroid/activities/ConfirmationActivity.kt
+++ b/app/src/main/java/eu/depau/etchdroid/activities/ConfirmationActivity.kt
@@ -1,9 +1,8 @@
 package eu.depau.etchdroid.activities
 
-import android.os.Bundle
-import android.app.Activity
 import android.content.Intent
 import android.os.Build
+import android.os.Bundle
 import android.view.View
 import android.widget.Toast
 import androidx.recyclerview.widget.LinearLayoutManager
@@ -15,13 +14,43 @@ import eu.depau.etchdroid.img_types.DMGImage
 import eu.depau.etchdroid.kotlin_exts.*
 import eu.depau.etchdroid.services.UsbApiDmgWriteService
 import eu.depau.etchdroid.services.UsbApiImgWriteService
-
+import eu.depau.etchdroid.utils.DoNotShowAgainDialogFragment
 import kotlinx.android.synthetic.main.activity_confirmation.*
 import java.io.IOException
 
 class ConfirmationActivity : ActivityBase() {
     var canContinue: Boolean = false
-    var issuesFound: Boolean = false
+    var issuesFound: String? = null
+    val DISMISSED_DIALOGS_PREFS = "dismissed_dialogs"
+
+    var shouldShowDataLossAlertDialog: Boolean
+        get() {
+            val settings = getSharedPreferences(DISMISSED_DIALOGS_PREFS, 0)
+            return !settings.getBoolean("data_loss_alert", false)
+        }
+        set(value) {
+            val settings = getSharedPreferences(DISMISSED_DIALOGS_PREFS, 0)
+            val editor = settings.edit()
+            editor.putBoolean("data_loss_alert", !value)
+            editor.apply()
+        }
+
+
+    fun showDataLossAlertDialog() {
+        val dialogFragment = DoNotShowAgainDialogFragment()
+        dialogFragment.title = getString(R.string.warning)
+        dialogFragment.message = getString(R.string.dataloss_confirmation_dialog_message)
+        dialogFragment.positiveButton = getString(R.string.confirm_flash_image)
+        dialogFragment.negativeButton = getString(R.string.cancel)
+        dialogFragment.listener = object : DoNotShowAgainDialogFragment.DialogListener {
+            override fun onDialogNegative(dialog: DoNotShowAgainDialogFragment, showAgain: Boolean) {}
+            override fun onDialogPositive(dialog: DoNotShowAgainDialogFragment, showAgain: Boolean) {
+                shouldShowDataLossAlertDialog = showAgain
+                nextStep(false)
+            }
+        }
+        dialogFragment.show(supportFragmentManager, "DataLossAlertDialogFragment")
+    }
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -102,13 +131,13 @@ class ConfirmationActivity : ActivityBase() {
             val imgRepr = StateKeeper.imageRepr as DMGImage
 
             if (imgRepr.tableType == null && (imgRepr.partitionTable == null || imgRepr.partitionTable?.size == 0)) {
-                part_table_header.text = getString(R.string.image_is_not_dmg)
-                issuesFound = true
+                issuesFound = getString(R.string.image_is_not_dmg)
+                part_table_header.text = issuesFound
                 return
             } else {
                 part_table_header.text = if (imgRepr.tableType != null) getString(R.string.partition_table_title) else ""
                 part_table_header_side.text = imgRepr.tableType?.getString(this) ?: ""
-                issuesFound = false
+                issuesFound = null
 
                 val viewAdapter = PartitionTableRecyclerViewAdapter(imgRepr.partitionTable!!)
                 part_table_recycler.apply {
@@ -120,9 +149,14 @@ class ConfirmationActivity : ActivityBase() {
         }
     }
 
-    fun nextStep() {
-        if (!canContinue) {
-            confirm_fab.snackbar(getString(R.string.cannot_write))
+    fun nextStep(showDialog: Boolean = true) {
+        if (!canContinue || issuesFound != null) {
+            confirm_fab.snackbar(issuesFound ?: getString(R.string.cannot_write))
+            return
+        }
+
+        if (showDialog && shouldShowDataLossAlertDialog) {
+            showDataLossAlertDialog()
             return
         }
 
diff --git a/app/src/main/java/eu/depau/etchdroid/activities/StartActivity.kt b/app/src/main/java/eu/depau/etchdroid/activities/StartActivity.kt
index 9423dde..307dd05 100644
--- a/app/src/main/java/eu/depau/etchdroid/activities/StartActivity.kt
+++ b/app/src/main/java/eu/depau/etchdroid/activities/StartActivity.kt
@@ -65,9 +65,10 @@ class StartActivity : ActivityBase() {
         val dialogFragment = DoNotShowAgainDialogFragment()
         dialogFragment.title = getString(R.string.here_be_dragons)
         dialogFragment.message = getString(R.string.dmg_alert_dialog_text)
-        dialogFragment.closeButton = getString(R.string.i_understand)
+        dialogFragment.positiveButton = getString(R.string.i_understand)
         dialogFragment.listener = object : DoNotShowAgainDialogFragment.DialogListener {
-            override fun onDialogClose(dialog: DoNotShowAgainDialogFragment, showAgain: Boolean) {
+            override fun onDialogNegative(dialog: DoNotShowAgainDialogFragment, showAgain: Boolean) {}
+            override fun onDialogPositive(dialog: DoNotShowAgainDialogFragment, showAgain: Boolean) {
                 shouldShowDMGAlertDialog = showAgain
                 showFilePicker()
             }
diff --git a/app/src/main/java/eu/depau/etchdroid/utils/DoNotShowAgainDialogFragment.kt b/app/src/main/java/eu/depau/etchdroid/utils/DoNotShowAgainDialogFragment.kt
index 4b6c6a0..75da5d7 100644
--- a/app/src/main/java/eu/depau/etchdroid/utils/DoNotShowAgainDialogFragment.kt
+++ b/app/src/main/java/eu/depau/etchdroid/utils/DoNotShowAgainDialogFragment.kt
@@ -11,12 +11,14 @@ import kotlinx.android.synthetic.main.do_not_show_again.view.*
 
 class DoNotShowAgainDialogFragment() : DialogFragment() {
     var title: String? = null
-    var closeButton: String? = null
+    var positiveButton: String? = null
+    var negativeButton: String? = null
     var message: String? = null
     var listener: DialogListener? = null
 
     interface DialogListener {
-        fun onDialogClose(dialog: DoNotShowAgainDialogFragment, showAgain: Boolean)
+        fun onDialogPositive(dialog: DoNotShowAgainDialogFragment, showAgain: Boolean)
+        fun onDialogNegative(dialog: DoNotShowAgainDialogFragment, showAgain: Boolean)
     }
 
     override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
@@ -30,10 +32,15 @@ class DoNotShowAgainDialogFragment() : DialogFragment() {
                 .setTitle(title)
                 .setMessage(message)
                 .setView(dnsaLayout)
-                .setPositiveButton(closeButton) { _, _ ->
-                    listener?.onDialogClose(this@DoNotShowAgainDialogFragment, !doNotShowAgainCB.isChecked)
+                .setPositiveButton(positiveButton) { _, _ ->
+                    listener?.onDialogPositive(this@DoNotShowAgainDialogFragment, !doNotShowAgainCB.isChecked)
                 }
 
+        if (negativeButton != null)
+            builder.setNegativeButton(negativeButton) {_, _ ->
+                listener?.onDialogNegative(this@DoNotShowAgainDialogFragment, !doNotShowAgainCB.isChecked)
+            }
+
         return builder.create()
     }
 
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 47eee53..74a92b7 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -95,4 +95,8 @@
     <string name="here_be_dragons">Here be dragons</string>
     <string name="i_understand">I understand, continue</string>
     <string name="dmg_alert_dialog_text">While in most cases DMG images can be restored just fine, sometimes there may be inconsistencies. You\'ve been warned.</string>
+    <string name="confirm_flash_image">Flash image</string>
+    <string name="dataloss_confirmation_dialog_message">If you continue, selected image will be written and all data stored on the USB drive will be lost forever.</string>
+    <string name="warning">Warning</string>
+    <string name="cancel">Cancel</string>
 </resources>