Help please, stuck boot loop

[Amusick4889]

Ok guys,

HTC One M8 lit up last night by itself on the counter last night, when I checked it it had the HTC Powered by Android screen.

I finally got it to the screen in the attached photo.

When I tried record mode, it brought up a blank screen with a red triangle with a exclamation point in the middle and started a loop going to that and the HTC screen endlessly.

After that I got back to the reset screen and tried Factory Reset. This brought up a screen with two arrows making a circle with an arrow pointing down inside but made the same loop.

This phone has not been modified in any way. Any ideas?

 

[Amusick4889]

 

[Amusick4889]

After letting it go through the cycle a few times it came up with his and then turned off.

 

[dautley]

If you can get back to your bootloader (the first screen) tap the power button once then tap volume down to reboot and press the power button again. What happens next?

The second screen is the stock recovery screen. If you have a memory card installed you might try removing it and see if it boots up.

 

[Amusick4889]

It just goes back into the same loop no matter which option is chosen.

I've tried reboot and reboot fast boot under the fast boot menu as well as recovery and factory reset under the HBoot menu.

 

[dautley]

It looks like the operating system has been wiped, if it has never been tampered with I would see if it can be replaced under warranty. If not flashing a RUU might be able to get you back up and going. In order to find the right one we need to know your carrier. I also noticed your boot loader screen has no CID listed which is a bit odd.

 

[Amusick4889]

Carrier is ATT.

What is involved with flashing a RUU? I am a complete stranger to doing anything outside of syncing these phones.

 

[dautley]

It seems that AT&T has pushed out a update that could have been the cause of this. I would take it back to them for replacement as it has never been tampered with before. http://phandroid.com/2015/01/19/att-htc-one-m8-android-4-4-4-update/

 

[Amusick4889]

I'm thinking they did as well.

I took it to the device support center and they replaced the phone and SIM card no questions asked and I was out in 10 minutes.

Appreciate your help brother!