Sorry I could not connect before the forum. After I have commented about the battery, I had the same problems. I went for service and they told me it was a problem of the charging the battery sensor, so they changed it. But it has for nothing. Current problems: The screen is blocked and does not react at all, the percentage (%)of the battery is false, as it turns off as if the battery was empty, and until you connect the charger will not turn on again. reboots itself many times (5-7 times daily). I don´t now what else to try (I've tried almost everything in this forum, unless it is with root), and if I do not get anything this week, I'll send it next week to the factory, requesting a change of terminal (in warranty).
*If I could rootear without triping knox (I have a MJ7), I would do it to try the other ideas of our fellow forum. I do not mind rooting, but I mind having a big paperweight.
A hug to all and hope that we all find the solution.