Upgrade attempt returns "2. run" and hangs

[sreknob]

Thanks for putting this together. Just a note, not really an issue as it worked on second attempt.

First time I tried to upgrade, I got 2. run after CEL stick and it just hung there.

After I stopped the script I re-plugged my stick and it worked fine.

Not certain if it should be recommended to cycle/reboot the stick prior to running this. This one had a few months of uptime on it.

root@ad504461efa8:/tmp/silabs# ./ncp.py scan
Connecting to.. /dev/ttyUSB1 57600 True False 
{"ports": [{"stackVersion": "5.4.1-194", "deviceType": "zigbee", "pid": "8A2A", "port": "/dev/ttyUSB1", "vid": "10C4"}]}
root@ad504461efa8:/tmp/silabs# ./ncp.py flash -p /dev/ttyUSB1 -f ncp-uart-sw-6.6.5.ebl 
Restarting NCP into Bootloader mode...
CEL stick
2. run

^CTraceback (most recent call last):
  File "./ncp.py", line 449, in <module>
    flash(args.port,args.file)
  File "./ncp.py", line 315, in flash
    ser.readline() # 2. run
  File "/usr/local/lib/python2.7/dist-packages/serial/serialposix.py", line 483, in read
    ready, _, _ = select.select([self.fd, self.pipe_abort_read_r], [], [], timeout.time_left())
KeyboardInterrupt
root@ad504461efa8:/tmp/silabs# ./ncp.py scan
Connecting to.. /dev/ttyUSB1 57600 True False 
Exception: <class 'serial.serialutil.SerialException'> /dev/ttyUSB1 
{"ports": [{"deviceType": "unknown", "pid": "8A2A", "port": "/dev/ttyUSB1", "vid": "10C4"}]}
root@ad504461efa8:/tmp/silabs# ./ncp.py scan
Connecting to.. /dev/ttyUSB1 57600 True False 
{"ports": [{"stackVersion": "5.4.1-194", "deviceType": "zigbee", "pid": "8A2A", "port": "/dev/ttyUSB1", "vid": "10C4"}]}
root@ad504461efa8:/tmp/silabs# ./ncp.py flash -p /dev/ttyUSB1 -f ncp-uart-sw-6.6.5.ebl 
Restarting NCP into Bootloader mode...
CEL stick
EM3581 Serial Bootloader v5.4.1.0 b962

Successfully restarted into bootloader mode! Starting upload of NCP image... 
Finished!
Rebooting NCP...
root@ad504461efa8:/tmp/silabs# ./ncp.py scan
Connecting to.. /dev/ttyUSB1 57600 True False 
{"ports": [{"stackVersion": "6.6.5-204", "deviceType": "zigbee", "pid": "8A2A", "port": "/dev/ttyUSB1", "vid": "10C4"}]}
root@ad504461efa8:/tmp/silabs#