[Nexus 7 Q&A, Help & Troubleshooting] Wornout:
Hello there everyone.

First off, I know this might seem like a subject that's already been covered. Trust me, I've spent the last few days going through every thread I could find on here trying everything out as well as other threads on tips on the net. So I'm posting this because I've tried everything and run out of troubleshooting methods to have a go with. The experts here may relish the challenge of solving this one. Or tear their hair out just like I'm doing. Hence my username. I'm worn out after countless hours of doing this.

Background:

I had a rooted Nexus 7 with superuser and TWRP. Jellybean 4.2.1 update would never work, always got an assert failed or some other error when it tried to do so. I then decided to go back to a previous backup in case something had gone wrong since in order to get on with installing the update.

Previous backup loaded fine. Unfortunately WiFi was not working and just kept on searching forever. After lots of googling and trying all the fixes with my router and so on which failed to solve anything, took the advice of going back to a factory reinstall.

Reinstalled, booted up, selected language on Google Welcome Screen then onto Wifi screen. Stuck on seaching forever. More googling and took advice. Decided to do Nexus Root Toolkit's flash stock+unroot to get back to clean state. After install there's an issue that just won't go away and that is:

Problem:

Google Nexus 7 (Wifi model) won't go past Google screen (this is not the coloured logo, just the word "Google" in white).

Associated problems:

Going into recovery just shows the same screen or sometimes an android lying on its back with a red triangle.. So no stock recovery available. Using fastboot to lock and unlock the bootoader as a recommended fix has no apparent effect with the result just being the same Google screen (padlock icon unolocked or locked depending upon locking status) even after a long wait.

Flash stock+Unroot in Nexus Root Toolkit has the same result. I left the thing on for a long time each time after a factory install because of advice saying to wait and still the same screen all that time. Longest time was 6 hours left on due to frustration and waiting to see if anything at all would happen. It didn't.

I can't access ADB in bootloader. I can only access ADB when the device is in TWRP or CWM menus. (In other words Nexus Root Toolkit complains it can't connect when I'm in the bootloader for example if I want to do any operation that requires ADB, but doesn't complain when in in those two recovery menus). Nexus Toolkit will quite happily do the Flash stock+ unroot and get to the screen where it says wait a while for device to reboot and you can press any key to exit.

I have wiped system, cache, boot, recovery, userdata using both fastboot and JROM Flasher. I can install TWRP or CWD using the Nexus Toolkit and wipe stuff using those but still no joy. I have gone through every permutation many times step by step. I have even used different Jellybean factory images from 4.1.0 to 4.2.1 as well as past backups with the same result each time.

Have used soft bricked and device is on options in Roolkit. No joy.

I have also disconnected the battery as part of the troubleshooting process.

Basically, nothing I can do using the information I've been able to get hold of can get past that screen.

Other quirks:

I have also noticed when installing a factory image a message comes up:

writing bootloader FAILED (remote: (invalid state))

It continues with the rest of the installation however as normal.

Also PdaNet comes up with the message:

Wrong WinUSB Pipes found

If I try Connect Internet (USB) option.

I have downloaded Nexus 7 tablet USB driver revision R06 and tried to use them but my PC will only recongise the device as an MTP device with failed driver install when the tablet is in that endless Google screen.

With the install of the Naked Universal Driver it only recognises the device in the Device Manager as Google Nexus 7 Bootloader Interface.

Driver tests in Nexus Root Toolkit fail. It advises enabling USB debugging as one of the fixes which of course I cannot do as I can't boot up to reach those options.

From this I surmise there is some problem with the drivers. I have tried on two different PCs as well.

Software I have used in all my efforts: Nexus Root Toolkit 1.6.2, Gnex, JROMFlasher, TWRP, CWM, PdaNet, SDK Manager, Nexus 7 tablet USB driver revision R06, Naked Universal Driver 0.72 .

I'd appreciate any advice (apart from sending the thing back), epescially if it's in a step by step easy to follow format. So basically, my question is, how do I fix this? Is it possible to fix?

Many thanks in advance!