"Why won't my phone charge?"に関する回答The only thing that works to solve the issue is POWER + VOL UP for 11-45 seconds (until something appears on screen) then plug in a good charger. I have been experiencing this issue off and on for over a year and even got a replacement from HTC which has the same issue. In my opinion it has nothing to do with cords, bricks, or the port. I have had many other issues with HTC One M9 (overheat, unexpected battery drain, etc.) and will NEVER buy another HTC device.