error while running python script to exploit UART attack on raspberrypi3 using attify-badge

[hammadvde]

hello,
i am trying to get access on my raspberrypi3 by attacking UART using attify-badge. i want to dump memory of my raspberrypi and get the root access of my PI (hardware hacking). i connected the UART pins of my pi in GPIO pins of PI with my attify-badge UART pins. (transmitter pin on my pi connected with receiver pin on my attify-badge and receiver pin on my pi connected with transmitter pin on my attify-badge). i have selected baudrate = 115200
this is what it displays when i start my attify-badge:

[] UART_getport invoked
[] Enabling Adafruit FTDI
[] Setting up GPIO pins
[] JTAG_getcfg invoked
[] UART Connect invoked
[] UART Connect executed Successfully
[] Serial port opened
[] Initializing ConsoleReadThread
[*] Starting UARTConsoleReadThread

then when i switch off my pi and then again plug in back to reboot my PI. i see this error on cmd prompt:

Traceback (most recent call last);
File "main.py" , line 102, in UART_read
if(len(str(QString))>0:
UnicodeEncodeError: 'ascii' codec can't encode character u'\xff' in position 0: ordinal not in range(128)

and on attify-badge tool GUI, i see this:

welcome to the rescue system:

recovery login:

can someone help me solve this issue?? thanks in advance :)