hey my name is jordan, I was having charging problems with my HTC One M8. it for the lif of it couldnt keep a charge i thought it was my charger cable at first so i tried multiple chargers with the HTC wall adapter and still nothing. eventually my battery just kept draning even with it plugged in untill my phone started dying and i was having a difficult time trying to power it on. so i did some researching and found that if i held the {POWER BUTTON} And the {VOLUME DOWN BUTTON} For 2 Minutes (Yes i know that sounds ridiculous} and to my surprise it started charging again. supposedly doing so recalibrated my battery settings and wahlahhh FIXEDD! very happy hope this helps