Originally Posted by suprtrukr425
Tried this. It did seem to work for me. I was skeptical, but I definitely feel like it fixed the erratic battery behavior I was seeing.
Sent from my HTC One_M8 using XDA Premium 4 mobile app
According to HTC tech support, the battery in the One has a chip that tracks charging/discharging. This chip's memory is cleared via the specific steps I outlined (both volume keys and power button cycling). It's important to do this process while the phone is plugged into the HTC charger that came with the phone--not an aftermarket charger. Apparently, the charger chip is also affected by this reset.
I performed this reset procedure a few times, cleared the device cache, did a data reset, and also installed the new OTA. None of these steps completely corrected my erratic battery behavior. I'm sending the phone back to HTC for a replacement. In researching this, it appears that after the prior KitKat OTA several weeks ago, a number of folks have complained of the same power problems on various Android boards and I believe HTC is aware of the problem.