This afternoon my (unrooted, bootlocked, stock) N5 turned itself off 3 times while on the charger. Powered back on and then would find it turned off 20 or so minutes later when I checked it again. After the third time it booted to the "Google" screen and would go no further. I tried a hard reset but it gave an error. So I plugged it into my laptop and fired up Wug's NRT, unlocked the bootloader (at which point it got stuck at the same update screen described above for around an hour). I held power till it went off, booted back into bootloader (which showed as unlocked) and performed the flash to stock(+unroot) with softbrick/bootloop checked and ended up at the update animation again. Any thoughts other than RMA?
****Edit: Finally got the phone to boot after fastboot booting twrp. Was able to to wipe the phone (after multiple attemps blocked by can not mount storage/cache/etc/etc errors). Flashed 4.4 and the phone now boots to android BUT radio is non-functional (no signal despite being in my normal coverage area), any attempt to add an APN causes a hard reboot (had to go through all the setup screens again). Additionally, the phone won't turn off, even hard power downs (holding the button for 30 secs) lead to an immediate reboot. Still RMAing but I was able to relock the bootloader.