HTC one m8 fully stock [no root, s-on, locked] won't boot, doesn't seem to have os

[agraz]

f I try to regular boot up it loads white htc screen then goes black. Only way to get it to do anything is volume up + vol down + power until it shows charging. At this point I can vol down + power to bet into bootloader.

The phone is not recognized when plugged into computer while in the bootloader.

Tmobile phone

 

[redpoint73]

The phone is not recognized when plugged into computer while in the bootloader.

Recognized how? Even a fully working M8 won't be recognized by PC when phone is booted to bootloader, except with fastboot commands.

You mean T-Mobile US (there are also T-Mob European versions)? If so, try running the T-Mobile RUU with the phone in bootloader-fastboot mode:
http://www.htc.com/us/support/htc-one-m8-t-mobile/news/

Be aware the RUU will wipe all data on the phone. But I think you're past that point, anyway.

 

[agraz]

Yes it is Tmo US.
I tried running ruu, which picked up the phone, and stated the phone was running 6.20 which doesn't matter, I just want to get the thing turned on.
As RUU is running, it tells phone to reboot to bootloader and then it sits on the black htc load screen and doesn't do anything else.
I left it in this state for ~ hour with nothing happening.

 

[redpoint73]

As RUU is running, it tells phone to reboot to bootloader and then it sits on the black htc load screen and doesn't do anything else.
I left it in this state for ~ hour with nothing happening.

You will have to kill the RUU process (or reboot PC) and try again (possibly need to force reboot on the phone). The RUU says not to disconnect, but if it's been stuck for an hour, it's not going to proceed by itself.

Hopefully, running the RUU again will solve the issue. It's not unheard of where the RUU gets stuck, and folks need to run it again (and it works the second time).