i want update lg g3 can you help me !!!!G]

hi :o

i want lg g3 d850 modifie dont original but cart mere officiel at&t
i want version android 6 officiel or 5.1
I want you to help me in providing the appropriate version of the device
With an explanation of installation method images step by step
What do you advise me
:confused::confused::confused:

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