[TUTORIAL] How to unbrick Nexus 7 using NvFlash

[Calvin Hogg]

Hey everyone.

After recently hard-bricking my Google Nexus 7 2012 (nakasi/grouper) I managed to unbrick it using NvFlash. As the official guide only taught us how to back up the blob files, I had to experiment a bit.
So, after only a few hours of messing with NvFlash commands, I found a solution to unbrick the Nexus 7 by reflashing the bootloader.

IMPORTANT! This guide requires that you have already made a back up of your device's blob files by using AndroidRoot.Mobi's tutorial, located here: http://www.androidroot.mobi/pages/guides/tegra3-guide-nvflash-jellybean/

Step 1: Download and Install the APX Drivers
From a powered off state, connect your hard-bricked Nexus 7 to your computer, then hold down the power and volume-up buttons until your computer recognizes your device.
Download and extract the Universal APX Drivers package from the download section below. Open the Windows Device Manager, right-click on anything that resembles your Nexus 7 or an APX device and click Update Driver.
Instruct Device Manager to search for drivers in the recently extracted driver folder.
If Windows displays an error while installing the drivers, you may need to disable Driver Signature Enforcement via Windows Startup Settings.

Step 2: Set Up NvFlash
Download and extract the NvFlash package from the download section below. Open a terminal window in the recently extracted NvFlash folder. Ensure your Nexus 7 is in APX mode (power and volume-up).
Type "wheelie --blob blob.bin" without the quotes. If necessary, replace "blob.bin" with the location of your Nexus 7's blob.bin file.
NvFlash should now load, and the Google boot logo should appear on your Nexus 7.

Step 2.1 OPTIONAL: Boot the system
To test NvFlash's connection with your Nexus 7, type "nvflash -r --download 5 eks.img" without the quotes. If necessary, replace "eks.img" with the location of your Nexus 7's blob.bin file. Your Nexus 7 should reboot into the ROM you previously had installed. Just keep in mind this is a temporary way of bypassing the bootloader to boot the system; the device is technically still bricked.

Step 3: Flash the bootloader
Type "nvflash -r --download 4 bootloader.img" without the quotes. Replace "bootloader.img" with the location of the bootloader found in any Nexus 7 stock factory image. NvFlash will flash the bootloader and boot to Android.

Step 4: Access the bootloader
By now, your Nexus 7 should be unbricked. However, to be on the safe side, I recommend that you reboot into the bootloader and flash whichever factory image you find to be the most stable.

Congratulations! If you completed the above steps and are able to access the bootloader, you have successfully unbricked your Nexus 7. I recommend that in order to prevent hard-bricks in the future, make as many backups of your "blob.bin" and "eks.img" files as you can. Keep them on multiple disks, upload them to the cloud, share them with your Facebook friends or even burn them to a CD. You cannot complete the above steps without them.

See you next time.

 

[amnher]

too bad I dont have a backup of the blob files. Is there a workaround for this? my nexus 7 is stuck on Erasing and I cant access bootloader no matter how I tried. Erasing is stuck no matter how many hours. It's stuck in erasing until its drain and when I full charge it and turn it on, it goes back to that.

 

[Calvin Hogg]

too bad I dont have a backup of the blob files. Is there a workaround for this? my nexus 7 is stuck on Erasing and I cant access bootloader no matter how I tried. Erasing is stuck no matter how many hours. It's stuck in erasing until its drain and when I full charge it and turn it on, it goes back to that.

As long as the device displays something on the screen, it's most likely not bricked.
Could you please post a screenshot of what's showing on the Nexus 7's screen, and tell me which version of Android you were using?

 

[amnher]

I am using the latest 5.1 image from google. I just factory resetted. The screen stayed with android mascot on the center and label "ERASING" but man hours has passed to the point of loosing battery but can't get pass through it. Upon loosing battery, it goes back to "ERASING". I cant still charge offline but if I turn it on it goes back to "ERASING" also. If in that screen I press UP+Power, it shows "Formatting /data" but it is stuck there.
Here are the Pictures:

 

[Calvin Hogg]

Are you able to access the bootloader? Try turning off your Nexus 7 and holding down the power and volume down buttons.
You should see a screen like this:

 

[amnher]

Before I can access that but now I can't. Everytime I try to hold power button to turn off it will reboot instead. If I try to hold vol down +power button before google logo appears, theres no effect

 

[Calvin Hogg]

From recovery mode, hold the power button until the screen goes blank, then immediately release the power button. After that, immediately hold the power and volume down buttons BEFORE the Google logo appears.
This is because the bootloader is a low-level part of the device, and appears before anything else.
If you wait until the Google logo appears before holding the volume down button, it will have been too late, and you'll need to try again.

 

[amnher]

From recovery mode, hold the power button until the screen goes blank, then immediately release the power button. After that, immediately hold the power and volume down buttons BEFORE the Google logo appears.
This is because the bootloader is a low-level part of the device, and appears before anything else.
If you wait until the Google logo appears before holding the volume down button, it will have been too late, and you'll need to try again.

yes that is what I am exactly doing. as soon as the screen goes blank i immediately press and hold power+vol down before google logo appears. After that all it does is either turns off again or go to that stuck ERASING part. I can do this on this nexus 7 before but now I can't. On my Nexus 5 I can do this trick to access bootloader

 

[Calvin Hogg]

yes that is what I am exactly doing. as soon as the screen goes blank i immediately press and hold power+vol down before google logo appears. After that all it does is either turns off again or go to that stuck ERASING part. I can do this on this nexus 7 before but now I can't. On my Nexus 5 I can do this trick to access bootloader

You could try the following:
- Open the Nexus 7 by sliding a credit card around the edge, and pulling it open with a fingernail
- Remove the battery's connector from its slot and leave it out for at least an hour
- Reconnect the battery and immediately hold the power and volume down buttons (with the cover off they look like little grey circles)

Refer to the images below for the location of the battery and power/volume buttons.

 

[adybaesu]

I have the same problem with my nexus stuck on APX mode . Bad news is i dont have a backup of the blob files... Is there another way to use your backup or something similar ?

 

[AndDiSa]

I have the same problem with my nexus stuck on APX mode . Bad news is i dont have a backup of the blob files... Is there another way to use your backup or something similar ?

Bad news for you: No, there is no chance. Either you've created 'your' blobs before or ...

 

[amnher]

You could try the following:
- Open the Nexus 7 by sliding a credit card around the edge, and pulling it open with a fingernail
- Remove the battery's connector from its slot and leave it out for at least an hour
- Reconnect the battery and immediately hold the power and volume down buttons (with the cover off they look like little grey circles)

Refer to the images below for the location of the battery and power/volume buttons.

Ill try that but you think that the volume down button can also be busted resulting not able to enter fastboot?

 

[mryorkshireman]

I did not get this problem mine was that I was getting the Supported API:3 loop and could not get into the bootloader to do anything. It may be that the answer I found may help you and other as I was at my wits end finding dead end fixes that did not work.

I had my problem with two Nexus 7 2012 tablets and have recovered them both this way.

While in the 'Supported API:3 ' loop ADB is loaded so you need to have the ADB/Fastboot drivers installed and working.

With your device attached to your PC go into the command prompt and type 'ADB Devices' without the quotes of course and hopefully it will show the ID of your tablet.
If it does then just Type' reboot bootloader' and it should boot into the bootloader.

Now you need to see if fastboot is working so type 'fastboot devices'. Again it should show you the ID of your device.
Download the latest stock update and extract the files. For the latest Nexus 7 2012 you will find the bootloader image file called 'bootloader bootloader-grouper-4.23.img'.
Type 'fastboot flash bootloader bootloader-grouper-4.23.img'
This will make sure you have the correct bootloader installed. Now type 'fastboot reboot-bootloader'

Your tablet should now boot into the bootloader again with no problem. To flash the stock image then type 'flash-all.bat' or if you wish type 'fastboot -w update image-nakasi-lmy47v.zip' then when that has finished type
'fastboot reboot' and set up your tablet again.

If you have problems make sure you have a good USB cable, the proper ADB/fastboot drivers installed and it has been suggested not to use a USB 3 port.

The only other trouble I had with one of my tablets was that when it rebooted it said that my data was encrypted or currupted and I had to enter my google password and once I found that fastboot did not work. I ran ADB devices and it found my tablet so I ran fastboot devices and it was ok then.

I could not get ADB to work at all in Windows 10 so I used Linux instead which does not need the drivers but does need the ADB/fastboot repository installed.

I installed VirtualBox on my Windows 10 laptop and installed Peppermint Linux in VirtualBox. This enabled me to get booted into bootloader on both occasions.

I realise that my problem was not the same but I hope at least it points you to a solution and you finally you have as good a result as I have and that this helps you.

 

[Charles IV]

I think I'm missing something. Does this also restore data, because i assumed the easiest way was to use Wugfresh's root toolkit, and that does the lot.

 

[janschrik]

My Nexus 7 was stuck in APX, I got the driver on it. As I have a second (working) Nexus 7 could i use the blob files from the second tablet and how should I progress in your tutorial?

 

[sam214]

Hi. My Nexus 7 was in bootloop so tried installing the stock firmware through the Nexus Root tool. The version was correct and so was the USB connection but it somehow got stuck in Installing Bootloader part for quite some time. I rebooted it and there was no display after that. I have the bootloader image from the stock firmware but can't install it as the Nexus Root Tool is not recognizing it as fast boot device. Is there a way to get it working? Thanks

 

[AndDiSa]

@sam214 nvflash is working for the Nexus 7 only if you have extracted your device specific binaries before. In that case you can restore the device with that binaries and get it running again. You cannot flash the extracted bootloader from the factory image with nvflash.

 

[TheDarkKnight]

@sam214 nvflash is working for the Nexus 7 only if you have extracted your device specific binaries before. In that case you can restore the device with that binaries and get it running again. You cannot flash the extracted bootloader from the factory image with nvflash.

Is there any way to unbrick without blobs?

 

[AndDiSa]

Is there any way to unbrick without blobs?

As far as I know: no, there is no way if your device is really bricked i.e. starts into APX mode only.
If the device does not start at all there is also the chance that "only" your battery power is too low ... so low that it does not even charge within the device. In that case there is the chance to revive the battery (there are several videos and instructions about that) if you are lucky.

 

[TheDarkKnight]

As far as I know: no, there is no way if your device is really bricked i.e. starts into APX mode only.
If the device does not start at all there is also the chance that "only" your battery power is too low ... so low that it does not even charge within the device. In that case there is the chance to revive the battery (there are several videos and instructions about that) if you are lucky.

My device only boots in APX mode So theres no way? What if I use blobs from someone with the same device?