diff --git a/tools/fw_server/fw-server.py b/tools/fw_server/fw-server.py
index 867d89709..536c76785 100644
--- a/tools/fw_server/fw-server.py
+++ b/tools/fw_server/fw-server.py
@@ -1,22 +1,23 @@
 #!/usr/bin/env python3
-
+# coding=utf-8
 """
-  fw-server.py - firmware server for Sonoff-Tasmota OTA upgrade
+fw-server.py - firmware server for Sonoff-Tasmota OTA upgrade
 
-  Copyright (C) 2018 Gennaro Tortone
+Copyright (C) 2018 Gennaro Tortone
 
-  This program is free software: you can redistribute it and/or modify
-  it under the terms of the GNU General Public License as published by
-  the Free Software Foundation, either version 3 of the License, or
-  (at your option) any later version.
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
 
-  This program is distributed in the hope that it will be useful,
-  but WITHOUT ANY WARRANTY; without even the implied warranty of
-  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-  GNU General Public License for more details.
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-  You should have received a copy of the GNU General Public License
-  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 Requirements:
    - Python3
@@ -31,26 +32,28 @@ Instructions:
         Firmware Upgrade -> Upgrade by web server
             http://<ip_address>:5000/sonoff-minimal.bin
 
+
 Usage:
-   ./fw-server.py -d <net_iface>   (default: eth0)
-		or
-	./fw-server.py -i <ip_address>
+    ./fw-server.py -d <net_iface>   (default: eth0)
+        or
+    ./fw-server.py -i <ip_address>
 
 Example:
-	./fw-server.py -d wlan0
-		or
-	./fw-server.py -i 192.168.1.10
+    ./fw-server.py -d wlan0
+        or
+    ./fw-server.py -i 192.168.1.10
 """
 
-import io
 import os.path
-from sys import exit
-from flask import Flask, send_file
 from optparse import OptionParser
+from sys import exit
+
+from flask import Flask, send_file
 import netifaces as ni
 
 
 usage = "usage: fw-server {-d | -i} arg"
+
 parser = OptionParser(usage)
 parser.add_option("-d", "--dev", action="store", type="string",
                   dest="netdev", default="eth0", help="network interface (default: eth0)")
@@ -58,23 +61,30 @@ parser.add_option("-i", "--ip", action="store", type="string",
                   dest="ip", help="IP address to bind")
 (options, args) = parser.parse_args()
 
+netip = None
+
 if options.ip is None:
-	try:
-		netip = ni.ifaddresses(options.netdev)[ni.AF_INET][0]['addr']
-	except Exception as e:
-		print("E: network interface error - {}".format(e))
-		exit(1)
+    try:
+        netip = ni.ifaddresses(options.netdev)[ni.AF_INET][0]['addr']
+    except Exception as e:
+        print("E: network interface error - {}".format(e))
+        exit(1)
 else:
-	netip = options.ip
+    netip = options.ip
+
 
 app = Flask(__name__)
 
+
 @app.route('/<filename>')
 def fw(filename):
-   if(os.path.exists("fw/" + str(filename))):
-      return send_file("fw/" + str(filename), attachment_filename=filename, mimetype='application/octet-stream')
-   else:
-      return("ERROR: file not found")
+    if os.path.exists("fw/" + str(filename)):
+        return send_file("fw/" + str(filename),
+                         attachment_filename=filename,
+                         mimetype='application/octet-stream')
+
+    return "ERROR: file not found"
+
 
 if __name__ == "__main__":
     try: