F670Lv9.0 Telnet Access

I want help to unlock my zte f670l, i cant access to telnet i tried the python scripts that has been given but it fails at 4th step giving me error..... Please help
 
Can you provide me with Zte F670l old firmware that has telnet enabled in it? And if possible any way to flash it without opening it, also thanks for giving out your time for replies really appreaciate it.
 
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