[Nexus 7 Q&A, Help & Troubleshooting] patil215:
Recently I have had a major issue with my nexus 7. About 2 weeks ago, it died (ran out of battery) while I was using it. When I attempted to turn it on after charging it, I would get the screen that says google, with unlocked lock icon. The tablet would be frozen at this screen. I left it running until it died again. I was running the latest stable release of cyanogenmod 10 with clockworkmod recovery with no problems before when this happened.

By now I had realized that the nexus may have been bricked. I did some googling and found that this is an issue other users have been having when their battery died on android 4.2.2. I attempted to restore the nexus. At this time I was able to access bootloader on the device by holding down all of the buttons at the same time. I think I selected the recovery option. However, I decided not to restore the nexus, and wait until a time where I would be able to turn all of my attention to the problem, and powered the device off, it may have been in recovery mode at that time but I do not remember.

But now, I can't access the bootloader! When I reboot the device by holding down power, I see the google screen for about 4 seconds, then I get a black screen (I can tell the device is still on because the screen is an illuminated black screen). Black screen remains there indefinitely. Any button combo (voldown+power, volup+power, all 3, volup+voldown (this one doesn't do anything), hard reset combo, etc) doesn't do anything except reboot the device and give me the same behavior.

I connected it to my pc (running windows 8) and used the nexus root toolkit by wugfresh to install some drivers. I could install the first driver the toolkit told me to but not the second because the device wouldn't reboot into bootloader. In device manager I see "Galaxy Nexus ADB Driver", hardware ids are USB\VID_18D1&PID_D001&REV_9999 and USB\Vid_18D1&PID_D001, so that tells me custom recovery. Running "adb devices" tells me the device is in recovery mode, but I just see a black screen. Doing adb reboot bootloader or fastboot reboot bootloader hangs and gives waiting for device respectively. Similarly wug's toolkit hangs when trying to reboot the device into bootloader.

I've opened up the back and done a literal battery pull many times. Battery connector is in place after this. I also accidentally broke off one of those tiny copper tabs next to the battery, but that's not relevant to this problem and I believe is minor, broke that after I got this problem. After I do battery pull and plug back in, I either:

a) get a battery lightning icon in the center of the screen, which begins to fill up after a few moments. Rebooting device gets me back into google then black screen mentioned above

b) get a screen with static/snow on it. There is also a hissing/humming noise coming from the back of it. Rebooting gets me to google screen again. This screen also can appear rarely with no discernable pattern to when it appears.

c) same google screen followed by illuminated black screen.

I've left the device charged in, unplugged it, let battery die, and tried many combos of buttons, but can't get anything except the three screens stated above.

I know the saying "Nexus devices are almost impossible to brick" but if I can't access the bootloader and just get black screen then I don't know if I can fix this.

I've posted a thread similar to this one before, so if your username is bftb0 then you've seen this problem already. I'm trying to repost with more information to see if any other ideas are there. Other thread is http://xdaforums.com/showthread.php?p=39522179#post39522179.

So these are my theories to what the problem is:

-corrupted bootloader

-bug/corrupted clockworkmod recovery

-bad battery/power/overheating

-corrupted memory

So how can I solve this?

I know there is NVFlash but there isn't a version for nexus 7. Almost all of the things I've found involve using bootloader. Any suggestions for things I haven't tried yet?

I have obtained an RMA from Asus but I don't want to send the device in because the bootloader is unlocked, so they would probably not cover this under warranty.

Does anybody know of a way to erase evidence of having a bootloader? Or a way to convince Asus to fix the device even with bootloader unlock? What's the price of the repair if not covered under warranty? I'm a poorish student with not much money, so I hope it's not that much and that's why I'm reluctant to pay for repairs.

Also I haven't done anything stupid like fastboot erase bootloader, in fact I hadn't connected the device to pc in a week.

I think this might be a bug with android 4.2. I love android and nexus, but if this is google's fault then I might be done with Android.

Thanks so much.