[GUIDE] Flashing a Factory Image with fastboot / return to stock

• Android SDK - adb, fastboot, usb drivers
• Java SE Development Kit - required by Android SDK
• A Nexus 7 factory image
• 7-Zip - used to extract factory images from a .tgz file

1. Download and install 7-Zip - http://www.7-zip.org/download.html
2. Download the Nexus 7 factory image - https://developers.google.com/android/nexus/images#nakasi and save it somewhere you can easily retrieve it.
   Make sure to download the correct image for your device variant (Wi-Fi vs GSM/HSPA+; nakasi vs nakasig)
3. Download and install the Java SE JDK - http://www.oracle.com/technetwork/java/javase/downloads/index.html
4. Download and install the Android SDK - http://dl.google.com/android/installer_r21-windows.exe
5. NOTE: Notice the install location. This defaults to C:\Users\<user name>\AppData\Local\Android\android-sdk the platform tools (adb, fastboot) and usb drivers will be downloaded to this location. This will be referred to from here on as your sdk directory
6. Run the SDK Manager
7. Under Tools, check the box labeled "Android SDK Platform-tools" - this provides adb and fastboot
8. Under Extras, check the box labeled "Google USB Driver"
9. Press the "Install # packages..." button and follow the on-screen instructions.
10. The platform tools will be installed at <your sdk directory>\platform-tools and the usb drivers will be in <your sdk directory>\extras\google\usb_driver

1. Enable usb debugging on your device (found under Settings > Developer Options)
   NOTE: Since Android 4.2 the Developer Options are hidden by default.
   To enable them, go to Settings > About Phone, and tap on build number around seven times. A small dialog will appear letting you know "You are now a developer!"
2. Install the abd driver - detailed instructions for installing or upgrading and existing driver on your version of Windows can be found at http://developer.android.com/tools/extras/oem-usb.html
3. Once the driver is installed open a command prompt and change directories to <your sdk directory>\platform-tools (see #2). From the command prompt run "adb devices". This will list any adb-capable devices that are connected to the computer by their serial number assuming your drivers are installed correctly. Recap:
   
   Code:

   > cd \Users\<user name>\AppData\Local\Android\android-sdk\platform-tools
   > adb devices
   # the following output should be returned
   List of devices attached
   <device serial number>       device

4. Use adb to boot the device to the bootloader:
   
   Code:

   > adb reboot-bootloader

5. The device should now be in fastboot mode and Windows should be attempting to install the fastboot driver. NOTE: if you had drivers previously installed, you may need to upgrade them. This is the same procedure described at http://developer.android.com/tools/extras/oem-usb.html
6. You can verify that the driver has been installed by running the following command:
   
   Code:

   > fastboot devices
   # the following output should be returned
   <device serial number>      fastboot

7. Do not proceed further if fastboot can not recognise your device. You are in driver hell and this must be resolved before continuing.

1. Use 7-Zip to open the factory image .tgz file. You should see a single .tar file. Open this file with 7-Zip as well.
2. Inside the .tar file is a directory that will resemble “nakasi-jwr66y”. Open that directory and extract the contents to <your sdk directory>\platform-tools.
3. The extracted files should be as follows: bootloader-grouper-4.23.img, image-nakasi-jwr66y.zip, flash-all.sh, flash-base.sh

1. Put the device into fastboot mode by running the following adb command:
   
   Code:

   > adb reboot-bootloader

2. In order to do anything useful in fastboot, the bootloader must be unlocked. To do this, run the following fastboot command:
   
   Code:

   > fastboot oem unlock

3. Follow the directions on the device, using the volume and power buttons to select "Yes". NOTE: this will wipe all personal data.
4. In fastboot with your device's bootloader unlocked, run the commands listed in flash-all.sh in sequence, waiting for each command to finish.
   Follow the commands for your device variant - Wi-Fi (nakasi) or GSM/HSPA+ (nakasig). For convenience I have them here:
   NOTE: you will see some messages about the archive not containing boot.sig, recovery.sig and system.sig. That is normal, dont worry.
   
   Wi-Fi devices (nakasi)
   
   Code:

   > fastboot erase boot
   > fastboot erase cache
   > fastboot erase recovery
   > fastboot erase system
   > fastboot erase userdata
   > fastboot flash bootloader bootloader-grouper-4.23.img
   > fastboot reboot-bootloader
   > fastboot -w update image-nakasi-jwr66y.zip

   
   GSM/HSPA+ devices (nakasig)
   
   Code:

   > fastboot erase boot
   > fastboot erase cache
   > fastboot erase recovery
   > fastboot erase system
   > fastboot erase userdata
   > fastboot flash bootloader bootloader-tilapia-4.23.img
   > fastboot reboot-bootloader
   > fastboot flash radio radio-tilapia-1231_0.18.0_0409.img
   > fastboot reboot-bootloader
   > fastboot -w update image-nakasig-jwr66y.zip

   After the final command completes, the device will reboot.
   
5. If you are sending the device in for warranty work, you may want to re-lock the bootloader
   
   Code:

   > fastboot oem lock

6. Finally, reboot the device
   
   Code:

   > fastboot reboot

Zenemon said:

Hi there. Having some trouble, hoping nothing serious. Read the guide twice and even went through the first 20 pages on this thread to see if any extra notes could be made.

Basically, let me start off by asking if its a problem installing google usb driver for nexus 7 v1 instead of the asus driver? I used the google driver that came with sdk tools and since everything seemed to work, i proceeded with command prompts.

2) When you extract bootloader-grouper-4.23.img, image-nakasi-jwr66v.zip, flash-all.sh, flash-base.sh to sdk platform tools, there is an omitted fifth file (.dat file). Should that not be included with everything else?

3) Heres where my actual problem seems to start.
Where your told to " fastboot flash bootloader bootloader-grouper-4.23.img" I get this error message:

Failed (remote: (invalid state)

4) Now the invalid state error seems connected to next command "fastboot -w update image-nakasi-jwr66v.zip" ( i had to rename to jwr66y.zip as thats what the zip file was called)
which resulted in this message:


"archive does not contain boot sig
archive does not contain recovery sig
not contain system.sig

bootloader version 4.18
baseband na
serial number ......

checking product...
checking version bootloader
failed

device version bootloader is 4.18
update requires 4.23
finished total time 0.210s


Not sure why this is happening because im 99% sure that followed commands to the letter. Seems tied up with bootloader not updating.
Ive really committed here and kind of sweating at this point :s

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fastboot flash bootloader bootloader-grouper-4.23.img

bbgt2 said:

Thanks for the reply bro, i got it flashed back to stock with WUG's tool so yet again I have escaped the need to learn ADB and ADK etc
Again thanks for the reply and making it sound fairly easy, now I wanna try it just for the next time I act like a moron and wipe a little too much before a new ROM install.

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Click to collapse

gb3338 said:

Nexus 7

"1.Enable usb debugging on your device (found under Settings > Developer Options)"

I don't see this option under settings, I think recent update of android to jop40c has made it vanish unless in a new location.

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