[One (M8) Q&A, Help & Troubleshooting] b.white:
Hello, new member here. I recently purchased an HTC One M8 from AT&T, unrooted to put superuser on my phone since I really disagree with an operating system telling me what I can and cannot do with the device I purchased. I did not know about S-OFF before this issue so no, it is currently S-ON I believe.

Just to be clear, my phone worked fine after this for ~2 months at least.

Anyways, to the issue. When I try plugging in my charging cable it says:

Although, I do have to say not even all the time. Most of the time when it's plugged in I get zero response that it is. It didn't use to be that way, this was a progression. It started charging fine, then the Car app started booting up asking to accept or decline. The car app doesn't even open up anymore.

So here I'm thinking, either the battery is broken, or the micro USB port.

However, I CAN charge the phone if I have fastboot turned ON and I turn off the phone. It's my understanding that fastboot only puts the phone in a hibernation state and it's not really turned off. When it is in this state, I can plug my charger in and I see the battery appear on the screen charging.

This is the only way I can charge my phone, by turning it off.

I cannot communicate with a PC, I cannot charge while it is turned on. This leads me to believe that this is in fact a software issue and not a hardware issue. However, this issue prevents me from communicating with a PC through USB which removes a number of options for me to test why this is happening.

I can transfer files over WIFI, and I have done so. Yesterday I transferred Android Revolution HD 11.1 to my phone over WIFI and was able to flash it, though I think I have a bad flash and just need to reflash due to a few minutes boot time, and I already read up that you need to try a few times until you get a fast response signifying you got a good image or something like that.

If anyone has any suggestions I am willing to try them, I have everything I need from the phone backed up. I have subscribed to this thread so I should receive a notification.

Tricks that I have tried:

Turning the phone on while the sensor is facing a bright light. Not sure why that would do anything but it was a common "solution".

Powering off the device and holding the power button as well as both volume buttons. This supposedly resets the "charge mode", no result. I was able to boot up to safe mode so I learned that I guess. No it doesn't charge in safe mode.

Draining the battery 100%, holding the power button until no response. Then charging. However, this was a nightmare, as when I tried doing this I got this guys problem: youtube.com/watch?v=r_Nll_01jG0 — This only happens when fastboot is off, or in this case, the power drained and the phone actually turned off, so it clearly only charges in hibernation.

Tricks that I have not tried:

Spraying the port with WD-40 while the device is turned off. Yea okay, I guess I'm worried about putting a liquid/oil in my phone.

They ended up only being tricks, not solutions to the problem. IF it was hardware I would understand completely. I no longer get a response from the phone when it is plugged in except for the occasional error message as the image above. HOWEVER, it charges in hibernation mode, every attempt, nothing weird, it just charges like it should. This is weird to me, because if it was hardware then this should not work. It makes no sense.

I tried an app called USB Host Diagnostics, I'm not sure if this is even going to provide any information to help or not but here is the result: usbhost.chainfire.eu/?search=455254

Since I've changed the ROM / OS of the phone to Android Revolution HD 11.1, and the problem still persists, then the next step down would be the... kernel? So it is either hardware or the kernel? That's just me guessing really... it's so hard to imagine it's the hardware. I take great care of my phone, never dropped it, don't overcharge it, I just don't understand what it could be other than the software of the phone just not recognizing the port while it is turned on, and whatever functions are turned on during hibernation are working correctly. Unless it's a voltage issue where it disables it to protect the motherboard, and during hibernation it isn't a risk, if that's even a thing. If it was a voltage thing, why then would it not charge when fastboot is turned off and the phone is off? It starts up with a battery on the screen then reboots in an endless loop like the video showed above. I just don't understand, wish there was something more to figure out other than it telling me that it's in host mode and can't charge, and by extension can't connect to a PC.