diff --git a/About.py b/About.py
index f9185fe..7599645 100644
--- a/About.py
+++ b/About.py
@@ -1,7 +1,9 @@
 
 # coding=utf-8
 
-import sys, os, wx
+import sys
+import os
+import wx
 import wx.html
 import wx.lib.wxpTag
 import webbrowser
@@ -29,10 +31,12 @@ class AboutDlg(wx.Dialog):
 
     <p>
     As with everything I offer for free, this is donation-ware.
-    <a href="https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=HFN4ZMET5XS2Q"><img src="{0}/images/paypal-256.png" width="256" height="88" alt="Donate with PayPal"></a>
+    <a href="https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=HFN4ZMET5XS2Q">
+    <img src="{0}/images/paypal-256.png" width="256" height="88" alt="Donate with PayPal">
+    </a>
     </p>
 
-    <p>&copy; 2017 Marcel St&ouml;r. Licensed under MIT.</p>
+    <p>&copy; 2018 Marcel St&ouml;r. Licensed under MIT.</p>
 
     <p>
         <wxp module="wx" class="Button">
@@ -57,7 +61,8 @@ def __init__(self, parent):
         self.SetClientSize(html.GetSize())
         self.CentreOnParent(wx.BOTH)
 
-    def _get_bundle_dir(self):
+    @staticmethod
+    def _get_bundle_dir():
         # set by PyInstaller, see http://pyinstaller.readthedocs.io/en/v3.2/runtime-information.html
         if getattr(sys, 'frozen', False):
             return sys._MEIPASS
diff --git a/HtmlPopupTransientWindow.py b/HtmlPopupTransientWindow.py
index 0d06847..eb22fe4 100644
--- a/HtmlPopupTransientWindow.py
+++ b/HtmlPopupTransientWindow.py
@@ -27,4 +27,4 @@ class HtmlWindow(wx.html.HtmlWindow):
         def OnLinkClicked(self, link):
             # get a hold of the PopupTransientWindow to close it
             self.GetParent().GetParent().Dismiss()
-            webbrowser.open(link.GetHref())
\ No newline at end of file
+            webbrowser.open(link.GetHref())
diff --git a/Main.py b/Main.py
index 7e84e93..c82d48b 100644
--- a/Main.py
+++ b/Main.py
@@ -1,9 +1,12 @@
 #!/usr/bin/env python
 
 import wx
+import wx.adv
 import wx.lib.inspection
 import wx.lib.mixins.inspection
-import sys, os
+
+import sys
+import os
 import esptool
 import threading
 import json
@@ -14,7 +17,7 @@
 from esptool import NotImplementedInROMError
 from argparse import Namespace
 
-__version__ = "2.2"
+__version__ = "3.0"
 __flash_help__ = '''
 <p>This setting is highly dependent on your device!<p>
 <p>
@@ -50,7 +53,9 @@ def write(self, string):
         else:
             wx.CallAfter(self.__out.AppendText, string)
 
+    # noinspection PyMethodMayBeStatic
     def flush(self):
+        # noinspection PyStatementEffect
         None
 
 # ---------------------------------------------------------------------------
@@ -210,7 +215,7 @@ def on_pick_file(event):
         reload_button = wx.BitmapButton(panel, id=wx.ID_ANY, bitmap=bmp,
                                         size=(bmp.GetWidth() + 7, bmp.GetHeight() + 7))
         reload_button.Bind(wx.EVT_BUTTON, on_reload)
-        reload_button.SetToolTipString("Reload serial device list")
+        reload_button.SetToolTip("Reload serial device list")
 
         file_picker = wx.FilePickerCtrl(panel, style=wx.FLP_USE_TEXTCTRL)
         file_picker.Bind(wx.EVT_FILEPICKER_CHANGED, on_pick_file)
@@ -322,7 +327,8 @@ def _select_configured_port(self):
                 break
             count += 1
 
-    def _get_serial_ports(self):
+    @staticmethod
+    def _get_serial_ports():
         ports = [""]
         for port, desc, hwid in sorted(list_ports.comports()):
             ports.append(port)
@@ -332,7 +338,7 @@ def _set_icons(self):
         self.SetIcon(images.Icon.GetIcon())
 
     def _build_status_bar(self):
-        self.statusBar = self.CreateStatusBar(2, wx.ST_SIZEGRIP)
+        self.statusBar = self.CreateStatusBar(2, wx.STB_SIZEGRIP)
         self.statusBar.SetStatusWidths([-2, -1])
         status_text = "Welcome to NodeMCU PyFlasher %s" % __version__
         self.statusBar.SetStatusText(status_text, 0)
@@ -356,7 +362,8 @@ def _build_menu_bar(self):
 
         self.SetMenuBar(self.menuBar)
 
-    def _get_config_file_path(self):
+    @staticmethod
+    def _get_config_file_path():
         return wx.StandardPaths.Get().GetUserConfigDir() + "/nodemcu-pyflasher.json"
 
     # Menu methods
@@ -380,13 +387,12 @@ def log_message(self, message):
 
 
 # ---------------------------------------------------------------------------
-class MySplashScreen(wx.SplashScreen):
+class MySplashScreen(wx.adv.SplashScreen):
     def __init__(self):
-        wx.SplashScreen.__init__(self, images.Splash.GetBitmap(),
-                                 wx.SPLASH_CENTRE_ON_SCREEN | wx.SPLASH_TIMEOUT,
-                                 2500, None, -1)
+        wx.adv.SplashScreen.__init__(self, images.Splash.GetBitmap(),
+                                     wx.adv.SPLASH_CENTRE_ON_SCREEN | wx.adv.SPLASH_TIMEOUT, 2500, None, -1)
         self.Bind(wx.EVT_CLOSE, self._on_close)
-        self.__fc = wx.FutureCall(2000, self._show_main)
+        self.__fc = wx.CallLater(2000, self._show_main)
 
     def _on_close(self, evt):
         # Make sure the default handler runs too so this window gets
@@ -412,7 +418,7 @@ def _show_main(self):
 # ----------------------------------------------------------------------------
 class App(wx.App, wx.lib.mixins.inspection.InspectionMixin):
     def OnInit(self):
-        wx.SystemOptions.SetOptionInt("mac.window-plain-transition", 1)
+        wx.SystemOptions.SetOption("mac.window-plain-transition", 1)
         self.SetAppName("NodeMCU PyFlasher")
 
         # Create and show the splash screen.  It will then create and
@@ -435,6 +441,8 @@ def main():
     app.MainLoop()
 # ---------------------------------------------------------------------------
 
+
 if __name__ == '__main__':
     __name__ = 'Main'
     main()
+
diff --git a/build-on-mac.spec b/build-on-mac.spec
index 2d4d6e2..3bba16c 100644
--- a/build-on-mac.spec
+++ b/build-on-mac.spec
@@ -2,7 +2,6 @@
 
 block_cipher = None
 
-
 a = Analysis(['nodemcu-pyflasher.py'],
              binaries=None,
              datas=[("images", "images")],
@@ -26,6 +25,6 @@ exe = EXE(pyz,
           upx=True,
           console=False , icon='images/icon-256.icns')
 app = BUNDLE(exe,
-             name='NodeMCU-PyFlasher.app',
+             name='NodeMCU-PyFlasher-3.0.app',
              icon='./images/icon-256.icns',
              bundle_identifier='com.frightanic.nodemcu-pyflasher')
diff --git a/build-on-win.spec b/build-on-win.spec
index 9b894f0..baaaf19 100644
--- a/build-on-win.spec
+++ b/build-on-win.spec
@@ -19,7 +19,7 @@ exe = EXE(pyz,
           a.binaries,
           a.zipfiles,
           a.datas,
-          name='NodeMCU-PyFlasher',
+          name='NodeMCU-PyFlasher-3.0',
           debug=False,
           strip=False,
           upx=True,
diff --git a/esptool.py b/esptool.py
index 3d1f0c9..571f6a3 100755
--- a/esptool.py
+++ b/esptool.py
@@ -33,7 +33,7 @@
 
 import serial
 
-__version__ = "2.2"
+__version__ = "2.2.1"
 
 MAX_UINT32 = 0xffffffff
 MAX_UINT24 = 0xffffff
@@ -183,10 +183,10 @@ def __init__(self, port=DEFAULT_PORT, baud=ESP_ROM_BAUD, trace_enabled=False):
         with ones which throw NotImplementedInROMError().
 
         """
-        if isinstance(port, serial.Serial):
-            self._port = port
-        else:
+        if isinstance(port, str):
             self._port = serial.serial_for_url(port)
+        else:
+            self._port = port
         self._slip_reader = slip_reader(self._port, self.trace)
         # setting baud rate in a separate step is a workaround for
         # CH341 driver on some Linux versions (this opens at 9600 then
@@ -265,18 +265,21 @@ def checksum(data, state=ESP_CHECKSUM_MAGIC):
 
     """ Send a request and read the response """
     def command(self, op=None, data=b"", chk=0, wait_response=True, timeout=DEFAULT_TIMEOUT):
-        if op is not None:
-            self.trace("command op=0x%02x data len=%s wait_response=%d timeout=%.3f data=%r",
-                       op, len(data), 1 if wait_response else 0, timeout, data)
-            pkt = struct.pack(b'<BBHI', 0x00, op, len(data), chk) + data
-            self.write(pkt)
-
-        if not wait_response:
-            return
-
         saved_timeout = self._port.timeout
-        self._port.timeout = min(timeout, MAX_TIMEOUT)
+        new_timeout = min(timeout, MAX_TIMEOUT)
+        if new_timeout != saved_timeout:
+            self._port.timeout = new_timeout
+
         try:
+            if op is not None:
+                self.trace("command op=0x%02x data len=%s wait_response=%d timeout=%.3f data=%r",
+                           op, len(data), 1 if wait_response else 0, timeout, data)
+                pkt = struct.pack(b'<BBHI', 0x00, op, len(data), chk) + data
+                self.write(pkt)
+
+            if not wait_response:
+                return
+
             # tries to get a response until that response has the
             # same operation as the request or a retries limit has
             # exceeded. This is needed for some esp8266s that
@@ -292,7 +295,8 @@ def command(self, op=None, data=b"", chk=0, wait_response=True, timeout=DEFAULT_
                 if op is None or op_ret == op:
                     return val, data
         finally:
-            self._port.timeout = saved_timeout
+            if new_timeout != saved_timeout:
+                self._port.timeout = saved_timeout
 
         raise FatalError("Response doesn't match request")
 
@@ -1839,6 +1843,9 @@ def write_flash(esp, args):
         if args.no_stub:
             print('Erasing flash...')
         image = pad_to(argfile.read(), 4)
+        if len(image) == 0:
+            print('WARNING: File %s is empty' % argfile.name)
+            continue
         image = _update_image_flash_params(esp, address, args, image)
         calcmd5 = hashlib.md5(image).hexdigest()
         uncsize = len(image)