HTC One M8 - Locked after Android 6 update So, I received a marshmallow update which buggered up the phone. After boot, it kept on saying android.process.acore has stopped with Google+ and an infinite loop asking me to report the error.

I don't know what I did but now I just get a screen saying:

*** Software Status: Modified ***
*** LOCKED ***
*** Security Warning ***
M8_UL PVT SHIP S-ON
HBOOT-319.0.0000


I'm stuck on this screen and none of the options do anything.


Hboot
Ramdump
Reboot
Reboot Fastfoot
Power down


What is going on?
I have recently discovered the same problem. Here are the steps which helped in my case (un-rooted phone just stopped loading after vacations):


I plugged in the cable to PC-USB. Th phone was not recognized.
I pressed on the phone something like "checksmartsd"
The phone was recognized by the PC and started as usual.


By "reboot" everything was fine. By "shut down" and "launch" the menu appeared again (phone not plugged to the pc). I chose the same "checksmartsd" and it worked.

I have no idea why it worked. I hope it helps somebody.

Best,
Eugene