diff --git a/lib/gui/app/models/settings.js b/lib/gui/app/models/settings.js
index 5f3dcd89..1002a407 100644
--- a/lib/gui/app/models/settings.js
+++ b/lib/gui/app/models/settings.js
@@ -37,6 +37,7 @@ const DEFAULT_SETTINGS = {
   errorReporting: true,
   unmountOnSuccess: true,
   validateWriteOnSuccess: true,
+  trim: false,
   updatesEnabled: packageJSON.updates.enabled && !_.includes([ 'rpm', 'deb' ], packageJSON.packageType),
   lastSleptUpdateNotifier: null,
   lastSleptUpdateNotifierVersion: null,
diff --git a/lib/gui/app/modules/image-writer.js b/lib/gui/app/modules/image-writer.js
index 6ea21e4a..e9ab6719 100644
--- a/lib/gui/app/modules/image-writer.js
+++ b/lib/gui/app/modules/image-writer.js
@@ -172,7 +172,8 @@ exports.performWrite = (image, drives, onProgress) => {
       uuid: flashState.getFlashUuid(),
       flashInstanceUuid: flashState.getFlashUuid(),
       unmountOnSuccess: settings.get('unmountOnSuccess'),
-      validateWriteOnSuccess: settings.get('validateWriteOnSuccess')
+      validateWriteOnSuccess: settings.get('validateWriteOnSuccess'),
+      trim: settings.get('trim')
     }
 
     ipc.server.on('fail', ({ device, error }) => {
@@ -200,6 +201,7 @@ exports.performWrite = (image, drives, onProgress) => {
         imagePath: image,
         destinations: drives,
         validateWriteOnSuccess: settings.get('validateWriteOnSuccess'),
+        trim: settings.get('trim'),
         unmountOnSuccess: settings.get('unmountOnSuccess')
       })
     })
@@ -312,6 +314,7 @@ exports.flash = (image, drives) => {
     flashInstanceUuid: flashState.getFlashUuid(),
     unmountOnSuccess: settings.get('unmountOnSuccess'),
     validateWriteOnSuccess: settings.get('validateWriteOnSuccess'),
+    trim: settings.get('trim'),
     applicationSessionUuid: store.getState().toJS().applicationSessionUuid,
     flashingWorkflowUuid: store.getState().toJS().flashingWorkflowUuid
   }
@@ -375,6 +378,7 @@ exports.cancel = () => {
     flashInstanceUuid: flashState.getFlashUuid(),
     unmountOnSuccess: settings.get('unmountOnSuccess'),
     validateWriteOnSuccess: settings.get('validateWriteOnSuccess'),
+    trim: settings.get('trim'),
     applicationSessionUuid: store.getState().toJS().applicationSessionUuid,
     flashingWorkflowUuid: store.getState().toJS().flashingWorkflowUuid,
     status: 'cancel'
diff --git a/lib/gui/app/pages/settings/templates/settings.tpl.html b/lib/gui/app/pages/settings/templates/settings.tpl.html
index 313c2cc2..5a0a5d64 100644
--- a/lib/gui/app/pages/settings/templates/settings.tpl.html
+++ b/lib/gui/app/pages/settings/templates/settings.tpl.html
@@ -43,6 +43,17 @@
     </label>
   </div>
 
+  <div class="checkbox">
+    <label>
+      <input type="checkbox"
+        tabindex="8"
+        ng-model="settings.currentData.trim"
+        ng-change="settings.toggle('trim')">
+
+      <span>Trim ext{2,3,4} partitions before writing (raw images only)</span>
+    </label>
+  </div>
+
   <div class="checkbox">
     <label>
       <input type="checkbox"
diff --git a/lib/gui/modules/child-writer.js b/lib/gui/modules/child-writer.js
index 84fcbdc0..ba613e7d 100644
--- a/lib/gui/modules/child-writer.js
+++ b/lib/gui/modules/child-writer.js
@@ -82,12 +82,10 @@ const terminate = (code) => {
  * @example
  * handleError(new Error('Something bad happened!'))
  */
-const handleError = (error) => {
+const handleError = async (error) => {
   ipc.of[IPC_SERVER_ID].emit('error', errors.toJSON(error))
-  Bluebird.delay(DISCONNECT_DELAY)
-    .then(() => {
-      terminate(EXIT_CODES.GENERAL_ERROR)
-    })
+  await Bluebird.delay(DISCONNECT_DELAY)
+  terminate(EXIT_CODES.GENERAL_ERROR)
 }
 
 /**
@@ -95,42 +93,45 @@ const handleError = (error) => {
  * @param {SourceDestination} source - source
  * @param {SourceDestination[]} destinations - destinations
  * @param {Boolean} verify - whether to validate the writes or not
+ * @param {Boolean} trim - whether to trim ext partitions before writing
  * @param {Function} onProgress - function to call on progress
  * @param {Function} onFail - function to call on fail
- * @param {Function} onFinish - function to call on finish
- * @param {Function} onError - function to call on error
- * @returns {Promise<void>}
+ * @returns {Promise<{ bytesWritten, devices, errors} >}
  *
  * @example
  * writeAndValidate(source, destinations, verify, onProgress, onFail, onFinish, onError)
  */
-const writeAndValidate = (source, destinations, verify, onProgress, onFail, onFinish, onError) => {
-  return source.getInnerSource()
-    .then((innerSource) => {
-      return sdk.multiWrite.pipeSourceToDestinations(
-        innerSource,
-        destinations,
-        onFail,
-        onProgress,
-        verify
-      )
-    })
-    .then(({ failures, bytesWritten }) => {
-      const result = {
-        bytesWritten,
-        devices: {
-          failed: failures.size,
-          successful: destinations.length - failures.size
-        },
-        errors: []
-      }
-      for (const [ destination, error ] of failures) {
-        error.device = destination.drive.device
-        result.errors.push(error)
-      }
-      onFinish(result)
-    })
-    .catch(onError)
+const writeAndValidate = async (source, destinations, verify, trim, onProgress, onFail) => {
+  let innerSource = await source.getInnerSource()
+  if (trim && (await innerSource.canRead())) {
+    innerSource = new sdk.sourceDestination.ConfiguredSource(
+      innerSource,
+      trim,
+
+      // Create stream from file-disk (not source stream)
+      true
+    )
+  }
+  const { failures, bytesWritten } = await sdk.multiWrite.pipeSourceToDestinations(
+    innerSource,
+    destinations,
+    onFail,
+    onProgress,
+    verify
+  )
+  const result = {
+    bytesWritten,
+    devices: {
+      failed: failures.size,
+      successful: destinations.length - failures.size
+    },
+    errors: []
+  }
+  for (const [ destination, error ] of failures) {
+    error.device = destination.drive.device
+    result.errors.push(error)
+  }
+  return result
 }
 
 ipc.connectTo(IPC_SERVER_ID, () => {
@@ -159,7 +160,7 @@ ipc.connectTo(IPC_SERVER_ID, () => {
     terminate(EXIT_CODES.SUCCESS)
   })
 
-  ipc.of[IPC_SERVER_ID].on('write', (options) => {
+  ipc.of[IPC_SERVER_ID].on('write', async (options) => {
     /**
      * @summary Progress handler
      * @param {Object} state - progress state
@@ -172,52 +173,20 @@ ipc.connectTo(IPC_SERVER_ID, () => {
 
     let exitCode = EXIT_CODES.SUCCESS
 
-    /**
-     * @summary Finish handler
-     * @param {Object} results - Flash results
-     * @example
-     * writer.on('finish', onFinish)
-     */
-    const onFinish = (results) => {
-      log(`Finish: ${results.bytesWritten}`)
-      results.errors = _.map(results.errors, (error) => {
-        return errors.toJSON(error)
-      })
-      ipc.of[IPC_SERVER_ID].emit('done', { results })
-      Bluebird.delay(DISCONNECT_DELAY)
-        .then(() => {
-          terminate(exitCode)
-        })
-    }
-
     /**
      * @summary Abort handler
      * @example
      * writer.on('abort', onAbort)
      */
-    const onAbort = () => {
+    const onAbort = async () => {
       log('Abort')
       ipc.of[IPC_SERVER_ID].emit('abort')
-      Bluebird.delay(DISCONNECT_DELAY)
-        .then(() => {
-          terminate(exitCode)
-        })
+      await Bluebird.delay(DISCONNECT_DELAY)
+      terminate(exitCode)
     }
 
     ipc.of[IPC_SERVER_ID].on('cancel', onAbort)
 
-    /**
-     * @summary Error handler
-     * @param {Error} error - error
-     * @example
-     * writer.on('error', onError)
-     */
-    const onError = (error) => {
-      log(`Error: ${error.message}`)
-      exitCode = EXIT_CODES.GENERAL_ERROR
-      ipc.of[IPC_SERVER_ID].emit('error', errors.toJSON(error))
-    }
-
     /**
      * @summary Failure handler (non-fatal errors)
      * @param {SourceDestination} destination - destination
@@ -234,24 +203,36 @@ ipc.connectTo(IPC_SERVER_ID, () => {
     }
 
     const destinations = _.map(options.destinations, 'device')
-    const dests = _.map(options.destinations, (destination) => {
-      return new sdk.sourceDestination.BlockDevice(destination, options.unmountOnSuccess)
-    })
-    const source = new sdk.sourceDestination.File(options.imagePath, sdk.sourceDestination.File.OpenFlags.Read)
-    writeAndValidate(
-      source,
-      dests,
-      options.validateWriteOnSuccess,
-      onProgress,
-      onFail,
-      onFinish,
-      onError
-    )
-
     log(`Image: ${options.imagePath}`)
     log(`Devices: ${destinations.join(', ')}`)
     log(`Umount on success: ${options.unmountOnSuccess}`)
     log(`Validate on success: ${options.validateWriteOnSuccess}`)
+    log(`Trim: ${options.trim}`)
+    const dests = _.map(options.destinations, (destination) => {
+      return new sdk.sourceDestination.BlockDevice(destination, options.unmountOnSuccess)
+    })
+    const source = new sdk.sourceDestination.File(options.imagePath, sdk.sourceDestination.File.OpenFlags.Read)
+    try {
+      const results = await writeAndValidate(
+        source,
+        dests,
+        options.validateWriteOnSuccess,
+        options.trim,
+        onProgress,
+        onFail
+      )
+      log(`Finish: ${results.bytesWritten}`)
+      results.errors = _.map(results.errors, (error) => {
+        return errors.toJSON(error)
+      })
+      ipc.of[IPC_SERVER_ID].emit('done', { results })
+      await Bluebird.delay(DISCONNECT_DELAY)
+      terminate(exitCode)
+    } catch (error) {
+      log(`Error: ${error.message}`)
+      exitCode = EXIT_CODES.GENERAL_ERROR
+      ipc.of[IPC_SERVER_ID].emit('error', errors.toJSON(error))
+    }
   })
 
   ipc.of[IPC_SERVER_ID].on('connect', () => {