[Nexus 7 Q&A, Help & Troubleshooting] Radiohead84:
Nexus 7 (2012)

4.4.4 Stock

KTU84P

HW Version - ER3

Bootloader Version - 4.23

Locked Bootloader

Not Rooted

I have a Nexus 7 sitting in front of me that was dropped off by my aunt in hopes that I could repair it for her. It doesn't look too promising, but I thought I'd consult the mighty fine people here on XDA before I give her the bad news. Here's what she says happened. Yesterday, while preforming day to day activities on it (browsing internet, Skyping, Facebook, etc), the device completely froze. After holding down the Power Button and forcing it to shutdown, she booted it back up. Everything seemed to functioned properly for about 30s - 1min when, at that time, the device turned off and rebooted on its own. After booting back up, it started to repeat this cycle. Basically getting stuck in a bootloop. I personally have never witnessed a bootloop like this before, where the device successfully boots up completely into the OS before turning off and repeating. I'm more used to dealing with ones where it might go as far as the manufacturer logo and then repeats. So anway, as I stated, I only have a 30s - 1min window where I can make changes in order to troubleshoot. The first thing I figured I should do was to go into "About Device", turn Developer Mode on and get USB Debugging enabled. I was able to do this and used "adb devices" to confirm its connection to my computer before it looped again. After its next bootloop I headed back into settings because I wanted to take note of the Android version she was running. As I was navigating there, I noticed that the Developer Options were no longer active. Basically as if I hadn't enabled them yet. This made me start thinking that changes being made on the device weren't sticking. I decided to make a few visual changes to the home screen and see if they were still there after the next bootloop. I uninstalled an app, rearranged icon placement, and changed the wallpaper. Once it shutdown and booted back up again, everything was back to the way it was before the changes had been made. The app I had uninstalled was still there, the wallpaper reverted back, and the icons were back in their original location. At this point I decided to see if I could reboot into Safe Mode. Unfortunately, this doesn't work. I am able to get the reboot to Safe Mode confirmation box and tap "Ok" but it remains in Normal mode when it boots back up. I eventually tried to boot into recovery and preform a Factory Reset. I was able to get into recovery and reset the Nexus. Or so I thought. Instead of seeing a Device Setup screen after it wiped, like I assumed I would, it booted up and still had all the data on it. There were no errors during the wipe and it was confirmed with "Data wipe complete." afterwards.

I am absolutely lost. I've never dealt with such an unusual issue before. Especially with it not even reacting to a complete data wipe. So, just to recap . . . I only have 30s - 1min available to interact with the OS before it reboots itself, any changes made during that time don't stick, Device is successful booting into Stock Recovery, and I can successfully get a Fastboot connection when booting to the Bootloader.

Luckily she has come to terms that this might not get fixed and has decided to go a head an order a newer 2013 model. I'd still like to try any solutions that you all might have. Just in case there is a slight glimmer of hope.

Oh, and one last thing I should mention. I tried to see if I could get the bootloader unlocked but it didn't work. This is the first Nexus I've ever had in my possesion, so I'm not really familiar with the tools available for it. I found WugFresh's Root Toolkit and attempted to Unlock with it. The process seemed to go as it should and I didn't receive any errors on the tablet or in the software. However, in the end, it didn't make any changes to the bootloader.