Just solved this problem, I am millet MIX2, started in March this year, the first two days began to charge slowly, it takes six or seven hours to be fully filled, how can this wait. Before slowing down, there is a new system update prompt, the mobile phone is not idle, it is not updated, and then change the charger, the data cable, it is still very slow, and it is still slow to update the system. Update today, download the full package (highlights), and then you're good to go. So it is necessary to update the system in time.