I cannot get my new radio (Baofeng model UV-5R-3 tri-band from MTC) to respond to a "Download From Radio" using CHIRP.  The radio shows no indication that it is being accessed.  My other Baofeng (regular UV-5R) is working on the same computer as expected.

The CHIRP version I am using :

CHIRP daily-20171126
GTK 2.24.10
PyGTK 2.24.0
Python 2.7.3

The CHIRP error message:

Error reading data from radio: not the amount of data we want.

Radio selected in CHIRP: BTECH UV-5X3

I understand that the driver (uv5x3.py) has been patched to include this new model, but its not working for me.
Are there any suggestions on how to cure this ...other than buy a better radio?