Default [Q] Nexus5: turning itself off, switches from ART to dalvik, no external storage

Hello,

I have created a simliar thread in the Nexus 5 subforum a while ago but didn't get much help or attention. My problem happended to me today again and I though maybe I crate a thread here to get more help.

I am running a Nexus 5 with everything stock 4.4.4, ART runtime, root enabled.

Some weeks ago my phone switched off automatically and when it rebooted it started to optimize my apps for dalvik. So after the crash it switched from ART to dalvik. I wiped it and installed everything fresh. On the same day it happened again. It just turned off and switched back to ART. I was running ART since I bought this phone and now it makes problems suddenly?

This morning I woke up and my phone was turned off. I switched it on and it took unusuallly long in the "google" screen and after the boot I was presented with the install wizzard. Also the phone tells me that I have not enough storage (no external storage).

Before wiping the phone completly again I first want to check how to save my files.

But does anybody know what is happening here?

EDIT: Also I have no connection to my provider anymore.

EDIT2: Tryed fo flash factory images but it keeps on failing: "FAILED (remote: flash write failure)".

Guess I have to send it to repair ... but it is rooted. Will google still take care of it?