New Nexus. Instructions on how to flash a Nexus device with the official firmware (Video) Nexus 7 firmware for cars

And you didn't like it?

Or maybe one of your family members (probably a cat - there’s no one else) installed Android 4.9.9 on it and now the tablet won’t boot? Or maybe you just need to give your tablet to a service center and you don’t want them to know that you experimented with the firmware? These are just a few of the reasons why you would want to restore to your tablet factory firmware. And today I will tell you how you can do this.

So, restoring the second generation Nexus 7 to factory firmware is quite easy, and for this you first need a computer with the Android SDK installed on it adb programs and fastboot.

In addition, do not forget to enable the “USB Debugging” option in the tablet settings. How to find USB debugging in the latest Android versions you can read in .

You will also need a system image of your tablet, which can be downloaded from the Google website. WiFi version of Nexus 7 sample 2013. It is codenamed “razor”.

Keep in mind that the first step we will need to take is to unlock the bootloader of your Nexus 7.

Note: If you have already unlocked it before, then you are “lucky” - since when performing this procedure all your personal data is lost, available on the tablet, so you first need to worry about backup.

Note 2: On a tablet with an unlocked bootloader it is quite easy to install modified recovery Clockworkmod or TWRP and you get root rights.

So, after you have installed on Android computer SDK, connected the tablet to it and made sure that the computer “sees” your device, you can begin restoring the factory firmware on your Nexus 7.

How to restore stock firmware on Nexus 7

1. Reboot your tablet into bootloader mode. This can be done by running in the window command line team

Alternatively, you can turn off the tablet completely and turn it on by pressing and holding the buttons at the same time decrease volume And inclusion. (Turn off, press volume down, then power button).

2. On your computer, in the command prompt window, enter the command

3. Confirm its execution on the tablet by selecting “Yes” by pressing the volume up button, and then the power button.

Attention !

This will erase all your personal data!

4. If you previously had your bootloader unlocked, steps 2 and 3 can be skipped.

5. Unpack the previously downloaded system image of your tablet into a separate folder on your computer.

If your bootloader was previously unlocked and you want to save personal data, find the file flash-all.bat (or flash-all.sh for a Linux computer) in the folder where you extracted the system image and remove –w from the line with the fastboot update command .

For example, if you see a line like: fastboot -w update image-razor-jss15j.zip, you need to make it look like: fastboot update image-razor-jss15j.zip.

6. Save the edited file.

Run the file flash-all.bat (or flash-all.sh for a Linux computer):

That's it, congratulations - you managed to return the stock version of the Android system to your Nexus 7. If you now want to install an alternative recovery on your tablet for further experiments with firmware, creating and restoring full backup copies

system and get Root, you, as an already experienced user, can do the following:

1. Installing TWRP recovery on Nexus 7 and getting root rights on the tablet Download the image to your computer from TWRP recovery

for your tablet from here. To do this, click on the "Get TWRP for your device" button and enter the name of the tablet in the window that opens (Nexus 7 2013) Download to tablet zip file with SuperSU from this post Google+ (mirror: UPDATE-SuperSU-v1.51.zip for getting root

2. in Android 4.3) Connect your tablet to your computer and boot it into bootloader mode ( adb command inclusion And decrease volume).

3. reboot bootloader or buttons

Enter the command in the command line window (terminal):

4. fastboot flash recoveryFileNameRecovery.img

Now you can preboot your tablet into a new recovery using the command: In addition, you can reboot the Nexus 7 into recovery mode by turning it off completely and turning it on by pressing and holding the buttons at the same time And inclusion.

5. increase the volume

6. Flash the zip file from SuperSU using TWRP (Install button -> select the zip file from the list and confirm the selection with the slider)

Reboot the tablet (Reboot -> System buttons) and update SuperSU from the Play Store.

That's it, now you have root on your tablet.

Android devices belonging to the famous NEXUS family are known for their reliability and long service life, which is ensured by technical components High Quality and well-developed software part of the devices. In the article brought to the attention of the reader we'll talk about the system software of the first tablet computer Nexus series, developed by Google in collaboration with ASUS, in the most functional modification - Google Nexus 7 3G (2012). Let's consider the firmware capabilities of this popular device, which is very effective in performing many tasks even today.

After reading the recommendations from the proposed material, you can acquire knowledge that will allow you to not only reinstall the official Android on the tablet, but also completely transform the software part of the device and even give it a second life, using modified (custom) Android options with extended functionality.

Despite the fact that the tools and methods of manipulating the internal memory of the device proposed in the material below have been used many times in practice, in general they have proven their effectiveness and relative safety, before proceeding to follow the instructions, it is necessary to consider:

Interfering with the system software of an Android device carries a potential risk of damage and is carried out by the user at his own decision after accepting full responsibility for any results of the manipulation, including negative ones!

As mentioned above, the methodology of methods that, as a result of their implementation, involve the implementation of Nexus 7 firmware, has been practically fully developed due to the widespread use of the device and its long service life. This means that following the proven instructions, you can reflash the tablet quite quickly and with virtually no problems. But any process is preceded by preparation and its implementation in full is very important to achieve a positive result.

Drivers and utilities

To seriously interfere with the system memory partitions of the device, a PC or laptop is used as a tool, and direct steps to reinstall software on an Android device are made using specialized utilities.

As for the software for Nexus 7 firmware, here for most operations the main tools are console utilities and. You can get acquainted with the purpose and capabilities of these tools in review articles on our website, and working through them in various situations is described in other materials available through search. Initially, it is recommended to study the capabilities of Fastboot, and only then proceed to follow the instructions from this article.

Of course, to ensure interaction between the firmware tools and the tablet itself, specialized drivers must be installed in Windows.

Installing drivers and console utilities

For a user who decides to flash the Nexus 7 3G firmware, there is a wonderful package, using which you can simultaneously get installed utilities for manipulating the device, as well as a driver for connecting it in software download mode - "15 seconds ADB Installer". You can download the solution from the link:

To avoid problems during the operation of the auto-installer and in the future when flashing the tablet firmware, disable the check before installing ADB, Fastboot and system components digital signature drivers.

1. We run the installer, that is, open the file "adb-setup-1.4.3.exe", obtained from the link above.

   

2. In the console window that opens, confirm the need ADB installations and Fastboot by pressing on the keyboard "Y", and then "Enter".
   
   
3. In exactly the same way as in the previous step, we confirm the request “Install ADB system-wide?”.
   
   
4. Almost instantly the necessary ADB and Fastboot files will be copied to HDD PC.
   
   
5. We confirm your desire to install drivers.
   
   
6. We follow the instructions of the launched installer.
   
   

   In fact, you only need to press a single button - "Further", the installer will perform the remaining actions automatically.

   

7. Upon completion of the tool, we obtain a PC operating system that is completely ready for manipulation of the Android device model in question.
   
   

   The ADB and Fastboot components are located in the directory "adb", created by the proposed installer in the root of the disk WITH:.
   
   

   The procedure for checking the correct installation of drivers is discussed below in the description of the device’s operating modes.
   

Multifunctional software package NRT

In addition to ADB and Fastboot, all owners of Nexus family devices are recommended to install the powerful multifunctional Nexus Root Toolkit (NRT) on their computers. The program allows you to carry out a lot of manipulations with any model from the family in question, and is successfully used to obtain root, create a backup, unlock the bootloader and completely flash devices. The use of individual functions of the tool is discussed in the instructions below in the article, and at the stage of preparing for the firmware, we will consider the process of installing the application.

1. Download the distribution from the official developer resource:

   

2. Launch the installer "NRT_v2.1.9.sfx.exe".
   
   
3. Specify the path where the tool will be installed and press the button "Install".
   
   
4. During the process of unpacking and transferring application files, a window will appear where you need to select the device model from the list and indicate the version of the firmware installed in it. In the first drop-down list, select "Nexus 7 (Mobile Tablet)", and in the second "NAKASIG-TILAPIA: Android *.*.* - Any Build" and then click "Apply".
   
   
5. The next window prompts you to connect the tablet with the "USB debugging" to PC. Follow the instructions of the application and click "OK".
   
   
6. After completing the previous step, the NRT installation can be considered complete, the tool will launch automatically.
   
   

Operating modes

To reinstall system software on any Android device, you will need to start the device in certain modes. For Nexus 7 this is "FASTBOOT" And "RECOVERY". So as not to return to this issue In the future, we will figure out how to switch the tablet to these states at the stage of preparing for the firmware.

Backup

Before moving on to flashing the Nexus 7 3G firmware, you should fully understand that the entire contents of the device’s memory will be destroyed during manipulations that involve reinstalling Android using any of the methods suggested below in the article. Therefore, if during the operation of the tablet it has accumulated information of any value to the user, obtaining a backup copy is definitely a necessity.

The ability to archive information and create a complete backup of the system was introduced by the developer into the aforementioned Nexus Root Toolkit application. Using the tool as a means to save data from the Nexus 7 3G and restore the necessary information later is very simple, and anyone, even a novice user, can figure out how to do this.

It should be noted that for the successful application of some methods Reserve copy using NRT requires that the tablet be equipped with a modified recovery environment (this component will be discussed later in this article), but, for example, applications with data can be backed up without prior manipulation of the device. We will create just such a copy according to the instructions below in order to understand how the information archiving tools offered by the Root Toolkit developer work.

1. We connect the device to the USB port of the computer, having previously activated it on the tablet "Debugging via USB".

   

2. Launch NRT and press the button "Backup" in the main application window.
   
   
3. The window that opens contains several areas, clicking on the buttons in which allows you to archive information various types and in different ways.

   

   Select an option "Backup All Apps" by clicking on "Create Android Backup File". You can first set checkboxes: "System apps+data" to save system applications with data "Shared data"— to add common application data (such as media files) to the backup.

   

4. The next window contains detailed description scheduled process and an instruction to enable the mode on the device "In airplane". Activate in Nexus 7 3G "Airplane Mode" and press the button "OK".
   
   
5. We indicate to the system the path where the backup file will be located, and also, if desired, indicate a meaningful name for the future backup file. Confirm your choice by pressing "Save", after which the connected device will automatically reboot.

   

6. Next, you should unlock the device screen and press "OK" in the NRT request window.
   
   

   The program will go into standby mode, and a request to start a full backup will appear on the tablet screen. Here you can specify a password with which the future backup will be encrypted. Next we tap "Back up data" and wait for the archiving procedure to complete.

   

7. Upon completion of saving the information to the backup file, Nexus Root Toolkit displays a window confirming the success of the operation "Backup complete!".

   

Unlocking the bootloader

The entire Nexus family of Android devices are characterized by the ability to officially unlock the bootloader, because these devices are considered reference devices for mobile OS development. For the user of the device in question, unlocking makes it possible to install custom recovery and modified system software, as well as obtain root rights on the device, that is, make it possible to achieve the main goals of most device owners today. Unlocking is very quick and easy using Fastboot.

All data contained in the device’s memory will be destroyed during the unlocking process, and the Nexus 7 settings will be reset to factory settings!

1. We start the device in mode "FASTBOOT" and connect it to the PC.
2. Open the Windows console.
   
   
3. We execute the command to go to the directory with ADB and Fastboot:
   cd c:\adb
   
   
4. We check the correct pairing of the tablet and the utility by sending the command
   fastboot devices

   

   As a result, the serial number of the device should be displayed on the command line.

5. To start the bootloader unlocking process, use the command:
   fastboot oem unlock

   

   Enter the instructions and press "Enter" on keyboard.

6. We look at the screen of the Nexus 7 3G - a request has appeared about the need to unlock the bootloader, requiring confirmation or cancellation. Select an item "Yes" using the volume keys and press "Nutrition".

   

7. Successful unlocking is confirmed by the corresponding response in the command line window,

   

   and later - the inscription "LOCK STATE - UNLOCKED", displayed on the screen of the device launched into the mode "FASTBOOT", and also the image of an open lock on the device’s boot screen every time it starts.

   

If necessary, the device bootloader can be returned to a locked state. To do this, follow steps 1-4 of the unlocking instructions presented above, and then send the command through the console:
fastboot oem lock

Firmware

Depending on the state of the software part of the Nexus 7 3G tablet, as well as on the owner’s ultimate goal, that is, the version of the system installed in the device as a result of the firmware process, the method of manipulation is selected. Below we consider the three most effective methods with which you can install an official system of any version “cleanly” and restore functionality operating system after serious software failures and, finally, give your Tablet PC a second life by installing custom firmware.

Method 1: Fastboot

The first method of flashing the device in question is perhaps the most effective and allows you to install the official Android any version, regardless of the type and build of the system installed in the device previously. And also, the instructions given below allow you to restore the functionality of the software part of those device instances that do not start in normal mode.

As for firmware packages, the link below presents all the solutions released for the model, starting with Android 4.2.2 and ending with the latest build - 5.1.1. The user can choose any archive based on his own considerations.

As an example, we will install Android 4.4.4 (KTU84P), since this option, according to user reviews, is the most effective for daily use. Using more earlier versions It is hardly advisable, and after updating the official system to version 5.0.2 and higher, there is a slight decrease in device performance.

Before starting manipulations according to the instructions below, ADB and Fastboot must be installed on the system!

1. Download the archive with the official system and unpack what you receive.

   

2. We put Nexus 7 3G into mode "FASTBOOT" and connect it to the USB port of the PC.

   

3. We follow the instructions for unlocking the bootloader if the action has not been carried out previously.
4. Let's launch executable file "flash-all.bat", located in the directory with the unpacked firmware.

   

5. The script will carry out further manipulations automatically; all that remains is to observe what is happening in the console window and not interrupt the process with any actions.

   
   Messages appearing on the command line characterize what is happening at each moment in time, as well as the results of operations to overwrite a particular memory area.

   

6. When the images are transferred to all partitions, the console will display the message “Press any key to exit...”.

   

   Press any key on the keyboard, as a result of which the command line window will be closed and the tablet will automatically reboot.

7. We wait for the components of the reinstalled Android to initialize and the welcome screen to appear with the choice of language.

   

8. After specifying the main OS parameters

   

   Nexus 7 3G is ready for use running the selected firmware version!

   

Method 2: Nexus Root Toolkit

Those users for whom the use of Windows applications for operations with the memory of Android devices seems preferable to the use of console utilities can take advantage of the opportunities provided by the multifunctional Nexus Root Toolkit mentioned above. The application provides an installation function official version OS included in the model in question.

As a result of the program, we get virtually the same result as when using the method described above via Fastboot - the device is in the “out of the box” state in terms of software, but with an unlocked bootloader. And NRT can also be used to “unscramble” Nexus 7 devices in simple cases.

1. Launch Root Toolkit. To install the firmware you will need an application section "Restore/Upgrade/Downgrade".

   

2. Installing the switch "Current status:" to a position corresponding to the current state of the device:
   • "Soft-Bricked/Bootloop"- for tablets that do not boot into Android;
   • "Device is on/Normal"- for device instances that are generally functioning normally.

   

3. We switch Nexus 7 to mode "FASTBOOT" and connect it with a cable to the USB connector of the PC.

   

4. For unlocked devices, we skip this step! If the device's bootloader has not been unlocked previously, do the following:
   
5. We begin installing the OS into the device. Click on the button "Flash Stock + Unroot".

   

6. Confirm with the button "OK" request from the program that it is ready to start the procedure.
   
   
7. Next window “Which factory image?” is intended for selecting the version and downloading firmware files. At the time of writing these instructions, only the latest version of the system for the Nexus 7 3G was able to be automatically downloaded through the program - Android 5.1.1 build LMY47V, the corresponding item must be selected in the drop-down list.

   

   Switch in the field "Choice" the described window must be installed in the position “Automatically download + extract the factory image selected above for me.” After specifying the parameters, press the button "OK". The download of the package with system software files will begin, wait for the download to complete, and then unpack and check the components.

   

8. After confirming another request - "Flash Stock – Confirmation"
   
   

   The installation script will be launched and the Nexus 7 memory partitions will be automatically overwritten.

   

9. We wait until the end of the manipulations - a window appears with information about how the tablet will start after reinstalling Android, and click "OK".

   

10. Next, a prompt is displayed to update the entry in NRT about the system version installed on the device interfaced with the utility. Here we also click "OK".

    

11. After completing the previous steps of the instructions, the device reboots into the OS automatically; you can disconnect it from the PC and close the NexusRootToolkit windows.
12. The bootlog can be displayed for up to 20 minutes during the first startup after the above operations, without interrupting the initialization process. You need to wait until the first screen of the installed OS appears, containing a list available languages interface. Next, we determine the main parameters of Android.

    

13. After the initial setup of Android, the device is considered completely reflashed
    
    

    and ready for operation running the latest version of the official system software.

    

Installing any version of the official OS via NRT

If latest version official Android on the device is not the result that is required from NRT; we should not forget that using the tool you can install into the device any assembly offered for use by its creators. To do this, you will first have to download the desired package from the official Google Developers resource. Full system images from the developer are available at the link:

We carefully select the package! Downloading software for the model in question should be done from the section entitled Identifier "nakasig"!

1. Download the zip file with the OS of the required version from the link above and, without unpacking, place it in a separate directory and remember the location path.
   
   
2. We follow the instructions for installing Android via NRT, suggested above. The steps for installing the package contained on the PC disk are almost exactly the same as the recommendations above.

   

   The exception is point 7. At this stage in the window “Which factory image?” do the following:

   
   
3. We are waiting for the installation to complete

   

   and reboot the tablet.

   

Method 3: Custom (modified) OS

After Google user Nexus 7 3G, methods for installing the official system into the device have been studied and tools have been mastered to restore the device’s functionality in critical situations; he can proceed to installing modified systems into the tablet. A large number of custom firmwares for the model in question have been released, because the device was initially positioned as a reference for the development of mobile OSs.

Almost all modified versions of Android developed for a tablet are installed the same way. The process is implemented in two stages: equipping the tablet with a custom recovery environment with advanced capabilities, and then installing an operating system from third-party developers using the recovery functionality.

Nexus 7 is a fairly popular tablet model from Google, which has captivated users with its combination of... good display and optimal performance. The device is remarkable in that it can easily be flashed with a custom version of the software or returned to the official Android system.

Google Nexus 7 is a very popular tablet model that is loved by users for its affordability, performance and stable operation.

The flashing process itself is simple, logical and consistent, so every user can easily understand it. Let's look at how to change correctly Nexus firmware 7, what is needed for this and what mandatory actions are required to work correctly with the tablet.

Preparing for firmware

We will divide the Nexus 7 into two stages - preparation, that is, installation of the required software on the tablet, and, in fact, the steps to download the new shell.

Before installing a new system on your device, you need the following:

1. Install tablet drivers.
2. Unlock the bootloader to be able to reflash the device.
3. , allowing you to interfere with system processes.
4. Load the Recovery menu, through which new software is installed.

To install drivers, follow these steps:

• Go to the gadget settings and in the “For Developers” section, activate the USB debugging function. If you suddenly don’t have such a line, go to the “About tablet” menu and click on the “Build number” line 7-8 times in a row until the message “You are now a developer!” appears.
• You will also need the “About the tablet” section to see the model build number. Write it down because it will come in handy later.
• Download the Nexus Root Toolkit program from the Internet, since flashing the device without it is impossible.
• Unpack and run the program, select “Full Drive Installation Drive - Automatic + Manual” from the menu.
• Next, click “Automatic Driver Configuration” for the seventh version of the system
• If you use another one or the drivers did not install yourself, you need to download them manually like this:
  • Go to your PC's device manager and find your tablet there.
  • IN context menu Click on update drivers.
  • Specify the path to the files: you should find the data/drivers folder, which is located in the Root Toolkit section of the program.

Now you need to unlock the bootloader on your Nexus 7. To do this, you need to do the following:

• In the main menu of the same Root Toolkit, click on Change, indicate the model build number that you wrote down earlier.
• Next, select Unlock, and when the tablet screen asks if you want to unlock it, agree.
• After this, the device may restart several times, and then again show the initial setup menu. Here, enable USB debugging again.
• When the unlocking starts, click OK in the program on your computer.

Note. If you need to take your tablet to a service center, but you don’t want them to find out about your actions with the firmware, because this will cause you to lose the warranty, you need to not only install the original version of the system, but also block the bootloader back. You can do this in the same Root Toolkit.

Let's move on to the third task - obtaining administrator rights. To activate them, you need to click on “Root” in the Root Toolkit, but first it is advisable to decide which one you will install on your device.

If you are going to use Clockworkmod, check the “Permanent CWM” option. But we recommend using another program called TWRP - it is considered more convenient and easier to use. In this case, you should check the “Do not flash...” option.

After selecting, click on the Root key itself so that the device reboots, after which you will receive administrator rights. If you decide to use the TWRP menu, install this application, after which the preparatory work before flashing can be considered complete.

By the way, a similar menu, Clockworkmod or TWRP, is also used to create backup copies of system data, clear it of cache and other information; in general, it is quite multifunctional and will be useful in subsequent use.

Firmware or flashing Nexus 7

How to flash Nexus 7? Let's proceed directly to the installation new system, for which we will do the following:

1. Need to choose new firmware. There are many of them, and different versions of the software can be found on many resources. global network in world wide web, they are in archive format.
2. After downloading, you should dump the archives on your Nexus 7 into a folder convenient for you.
3. Now you need to go to the Recovery menu - it is advisable to turn off the device, hold down the power and volume up keys at the same time for 10-15 seconds.
4. Next, you need to select from the menu Recovery Mode(navigation is carried out using the volume keys).
5. You need to reset all device data - to do this, select “wipe”, then “factory reset”.
6. After cleaning the gadget, it is advisable to return to the menu and find the Install line.
7. Now you just need to specify the path to the firmware file and select it, after which it will be installed.
8. If the firmware contains additional documents, you can install them after the main archive file.
9. Next, you need to restart Nexus

Note that switching on may take a little longer - this is a normal process, because the tablet is using the new system for the first time.

In front of you detailed step-by-step instructions about how to flash an ASUS Nexus 7 tablet. Our editors chose the most suitable way for flashing this ASUS model. If this instruction will not give results try flashing using another method: TWRP Recovery, ROM Manager, Fastboot or classic OTA.

Warning! After flashing the device, all your data from internal memory- will be erased, so to save your contacts, settings and applications, first save all data from your tablet.

System installation method CWM Recovery 1. Charge the flashed tablet at least 80%. 2. We save all data that cannot be lost from a flash drive, SIM card and tablet memory. The SIM card (if any) can be removed. 3. We place necessary firmware to the tablet's memory. The firmware file must be in archive format zip. You can select and download the firmware. 4. For everyone ASUS tablets it costs Recovery from the manufacturer, so we change it to ClockWorkMod Recovery. We do this according to the following instructions: Install the application from Google Play on your tablet. Launch it and provide Root rights . If there are no root rights on the tablet, we get them using . In the list of options, select “CWM Recovery”. Then the application will show a list of available Recovery. In the example, Rashr showed 2 options: ClockworkMod with support for taps on the screen and the classic version (controlled by the volume and power buttons). You will be prompted to download. Click Yes. Then the CWM Recovery image for the tablet will begin downloading. Ready. If you have already installed ClockworkMod Recovery, then simply enter it by pressing for 3-5 seconds any of the combinations: - Volume up + power button - Volume down + power button - Volume up/down + power button + "Home" - Volume up + volume down + power button 5. Movement in the Recovery menu is carried out using the volume buttons, and confirmation of the choice with the power button. Before installing the firmware, you must first do a factory reset. Therefore, select the item in the menu wipe data/factory reset.
6. Next, simply confirm that you agree to reset: Yes – Wipe all user data.
7. Now in the main menu of Recovery select install zip.
8. After that select Choose zip from /sdcard.
9. Navigate to the folder where you saved the firmware zip file and select it.
10. A confirmation message will appear. Select Yes – Install....
11. The firmware installation process will begin and at the end the message will appear Install from sdcard complete. The firmware is finished. We return to the main menu of CWM Recovery and reboot the tablet. For this we choose reboot system now.
12. Ready. The tablet will start loading from the already installed firmware. Other materials

Probably every user wanted to reflash their device because it was annoying stock firmware. Today I will tell you how to reflash Nexus 7 2013. Please, under the cut!

First, you need to understand whether you need this and why you are flashing your device - in this situation, Nexus 7. You should always remember that by flashing your device, you can turn it into a brick. If you do everything right, everything will work out! But remember, there is always a risk!

Then the user wants to know if the warranty expires? Of course! If you made a serious mistake while flashing your device and took it to the service center, then people will immediately notice that you messed around somewhere. However, traces of the crime can be covered up; below I will tell you how.

1) Let's flash it through Recovery (that is, with custom firmware)
If you decide to reflash your Nexus, then check the availability of drivers, the necessary software, and that the device is connected via USB. First, you need to get root rights.
Availability TWRP. Usually installed on Nexus via Nexus Root Toolkit.
Next you will need to select the firmware. Usually the firmware is in the .zip extension. There are tons of firmwares available for the Nexus 7 2013, so you have a choice) The most popular firmware site is xda-developers.com. Usually the developer indicates instructions for the firmware and its features. There are many more firmwares on 4pda. Some firmwares have additional .zip files. For example, in firmware CyanogenMod has a gapps installation package containing some parts of the system and Google services. These files are installed in the same way as the firmware.

Next, you need to upload the firmware files to the root of the memory card. Next we need to dive into TWRP, where we will reflash the files. (We go into Fastboot, then click Recovery Mode. After that we get into TWRP) Then we need to clear the data of the old firmware, or rather do a full reset. To reset the settings, click in TWRP on the Wipe tile, select there Factory Reset, click, agree and exit back to the menu
TWRP.

Now we have met the firmware. Click on the Install tile and install our firmware files (if there are gaps, then install more gaps). Confirm your choice and wait for the installation to complete. Then we do a reset. All is ready!

2) Let's flash the full image of the official firmware via ADB.

First you need to install the drivers through the Nexus Root Toolkit. Open the control panel and go to the device manager tab, find our Nexus device, and right-click Update Drivers. Specify the folder data\drivers, which is located in the Nexus Root Toolkit program folder.

Next you need to open the bootloader. You must indicate your device and firmware version. Press the button
Change, press the Unlock button. The tablet should reboot. When the question “Unlock Bootloader?” appears on the tablet display, select “Yes” by pressing the power button (on the tablet).
The tablet may reboot several times. Don't panic - this is normal. Eventually, sooner or later, you'll end up in the initial Nexus setup menu. After initial settings, again go to the tablet settings menu and in the developer section check the box for “USB debugging”.
In the Nexus Root Toolkit program window that opens after the unlocking process begins, click the “OK” button.

Then you need to download the official firmware image. We open it as a regular archive and see the folder, it must be extracted to the Nexus Root Toolkit/data/Factory_Images folder and do not leave it yet. We turn off our device and enter bootloader mode (in Fastboot). Connect it to the PC and return to that folder. We see the flash-all.bat file there and click on it. All flashing is finished, wait for it to finish and press the exit button. IMPORTANT! When flashing the firmware by running flash-all.bat, all data will be deleted, but this can be avoided if you open flash-all.bat using notepad and remove -w, Save from the last command.

How can I get my warranty back?

1. Restore original firmware via Nexus Root Toolkit.
2. Block bootloader

That's all. And remember, never worry during the flashing process. If something happens, don’t panic! Go online and enter your problem! There will be a solution. Thanks to all!