[Nexus 4 General] maxdak:
Boot and Baseband problems

Hi all,

Thank you to the active members for providing such a detailed source of reference material for everyone to use. There have been many, many times over the years that all I had to do was carefully read some posts in order to solve problem. My latest issue however refuses to respond to anything I've tried, so I am posting in hopes that someone might suggest something I have overlooked.

Problem Summary:

I have a 16GB Nexus 4 that seems to be in perfect physical condition. Since it was purchased about 7 months ago through Google, it has been unlocked, rooted, and running only the stock ROM. It had some hiccups with the OTAs released during that time, but otherwise ran ok. It stopped working on Tuesday.

The phone is used by a tech-illiterate parent so I don't know exactly what happened, but it seems like the cellular connectivity stopped working that morning. When the user tried rebooting the device--my recommended first course of action when there's a problem--it would no longer boot. Instead it would get stuck on the X boot animation.

Since Wednesday, I've tried dozens of fixes and solutions including the one that efrant so generously provided here. Most of them I've repeated several times or more in case further permutations were necessary (past experience has shown that small differences in conditions can affect outcomes). Unfortunately, I still cannot get the phone to a fully functional state.

Major Problems:

1) original boot problem--routinely stuck on X boot animation

2) ROM versions < 4.3 stick (boot properly) but "Baseband version" and IMEI fields are unknown/blank

Solutions Tried (abbreviated):

A) efrant's guide from this thread, along with suggestions made by various posters within

B) LG's LGNPST tool for Windows using Gigadroid's guide

C) N-Cry toolkit as described in a post by Cryten

D) restoring a backup provided by someone with a functioning 16GB N4 CWM backup--could never get past "Android is upgrading" screen despite various attempts including clearing caches, etc.

Notes & Observations:

- For some reason, the device will not boot any stock or custom ROM based on Android versions 4.3 or above (typically hangs on X boot animation). I have only been able to get 4.2.x versions to boot. For example, rolling back to JDQ39 seems to allow booting.

- Regardless of what ROM boots, I have not been able to get any cellular connectivity. Settings --> About phone shows unknown for Baseband version, and Settings --> About phone --> Status does not populate Network, Signal, or IMEI fields with the typical values.

- I've used an Ubuntu desktop and a Windows 8 desktop to work on the device. I've used the JDQ39, JWR66V, and JWR66Y stock images along with Cataclysm-jb-mr2-JWR66Y and CM 10.1.3 ROMs at various points. I have the latest Android SDK (adb, fastboot, etc.) files on the Windows 8 machine and recent or latest files on the Ubuntu machine. I've tried multiple radios including .27, .48, and .84. I've used stock recoveries when indicated, and also tried CWM Touch 6.0.3.8 and TWRP 2.6.0.0 and 2.6.3.0.

Conclusion:

Apologies for the length of this post. I wanted to provide detailed information to 1) assist with troubleshooting and 2) provide searchable terms and information for other users with this issue. This problem has occupied most of my waking hours for the last few days and I have mostly run out of things to try. I would greatly appreciate any insight or help into possible solutions, mistakes I may have made, etc. Thank you in advance!