Installing a local update on Android is a process that scares many users. Fears are associated with the risk of the device becoming bricked, data loss, or firmware incompatibility. However, in some cases, manual firmware becomes the only way to update a smartphone: when the manufacturer has stopped supporting the model, when automatic updating is stuck, or when you want to upgrade to custom firmware with advanced functions.

Unlike OTA updates (over the air), local installation requires active actions from the user: downloading the correct firmware file, preparing the device and choosing the appropriate installation method. In this article we will analyze all the current methods - from the simplest update via Recovery to advanced methods using ADB i Fastboot, and also tell you how to avoid common mistakes and what to do if something goes wrong.

Why install the update manually?

Automatic updates via Settings → System → Software update are convenient, but not always available. Here's when to consider a local installation:

  • 🔄 The manufacturer stopped supporting your model (for example, Samsung Galaxy S8 or Xiaomi Redmi Note 5), but enthusiasts have released unofficial firmware with the latest Android.
  • ⚡ The device does not receive OTA due to regional restrictions (for example, Google Pixel US firmware is not updated in Russia).
  • 🐌 Over-the-air update slows down at the download or installation stage (a common problem on cheap smartphones small memory capacity).
  • 🔧 You want to install custom firmware (for example, LineageOS or Pixel Experience) for advanced functions.
  • 🛠️ It is necessary to roll back to the previous version of Android after an unsuccessful update.

Local firmware is also useful if you testing beta versions of Android (for example, through the app Android Beta app for Pixel). In this case, manual installation allows you to avoid bugs that may arise during automatic updating.

⚠️ Attention: Some manufacturers (for example, Huawei or Honor) block the possibility of manual firmware on new models. Before you start, check if you are unlocked bootloader - without this, most methods will not work.
📊 How often do you update the firmware on your smartphone?
Only via OTA
Sometimes I install local updates
I use custom firmware
I never update

Preparing the device for a local update

An unprepared device is the main cause of failures during firmware. Follow this checklist to minimize risks:

☑️ What to do before flashing the firmware

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Pay special attention firmware selection. The file must correspond to:

  • 📱 Device models (for example, Samsung Galaxy A52 5G is SM-A526B, and not SM-A526U for the American market).
  • 🔢 Region (firmware for Europe may not be suitable for Asia due to differences in communication modules).
  • 🔄 Android versions (You cannot install Android 14 on a device that officially supports only Android 12).

Download firmware only from official sources:

⚠️ Attention: Firmware files often weigh 2-4 GB. Download them over a stable Wi-Fi connection, and not through the mobile data - an interrupted download may lead to file corruption.

If you plan to use ADB or Fastboot, install on your PC:

  • 🖥️ Platform Tools from Google (includes adb, fastboot).
  • 🔌 Drivers for your device (for example, Samsung USB Drivers or MediaTek Preloader).

Methods for installing a local update

The choice of method depends on your device model, whether it is unlocked bootloader, and what firmware file you have. Let's consider all current options.

1. Update via Recovery (the safest method)

This method is suitable if you have a firmware file in the format .zip (for example, OTA update or custom firmware). unlock bootloader and is suitable for most devices.

Instructions:

  1. Download the firmware and rename the file to update.zip (for convenience).
  2. Move the file to the root directory of the internal memory or to SD card.
  3. Turn off the device and hold down the combination of buttons to enter Recovery:
    • For Samsung: Power + Volume Up + Bixby.
    • For Xiaomi/Redmi: Power + Volume Up.
    • For Google Pixel: Power + Volume Down, then select Recovery Mode.
  • In the menu Recovery select Apply update from SD card or Apply update from ADB (if the file is on a PC).
  • Select file update.zip and confirm installation.
  • After completion, select Reboot system now.

    • If Recovery there is no option to install updates, then your device uses stock recovery without such. functions. In this case, you will have to use ADB Sideload (see the next method).

    What to do if Recovery does not see the update.zip file?

    Check that the file is actually called update.zip (case is important!). If the problem persists, try:

    1. Transfer the file to the SD card (sometimes the internal memory is not readable in Recovery).

    2. Use a different name format (for example, just update without .zip).

    3. Check the file for integrity (it may have been downloaded with an error).

    2. Installation via ADB Sideload

    Method ADB Sideload suitable if your device does not support installation .zip directly from Recovery, but you have access to ADBThis is true for many devices Google Pixel, OnePlus and some models Xiaomi.

    Step-by-step. instructions:

    1. Download the firmware and rename it to update.zip.
    2. Connect the device to the PC via USB (use the original cable!).
    3. Boot into Recovery Mode (see button combinations above).
    4. In the menu Recovery select Apply update from ADB.
    5. On the PC, open the command line in the folder with platform-tools and enter: 
      adb devices

      Make sure that the device is detected.

    6. Enter the command for installation: 
      adb sideload update.zip
    7. Wait for the process to complete (progress will be displayed both on the PC and on the device screen).
    8. After installation, select Reboot system now.

      9. If the process is interrupted with an error adb: failed to read command: No error, try:

      • 🔌 Use another USB cable (preferably the original one).
      • 🖥️ Reinstall the drivers ADB on the PC.
      • 🔄 Reboot the device and PC.

    3. bootloader)

    This method requires unlocked bootloader and is suitable for devices with chips Qualcomm (most flagships Samsung, OnePlus, Xiaomi). Firmware via Fastboot allows you to install a full system image, including boot, recovery and other sections.

    Important: Unlocking bootloader resets the device to factory settings! Make a backup copy in advance.

    Instructions:

    1. Unzip the downloaded firmware (usually this is a folder with files .img).
    2. Connect the device to the PC and boot into Fastboot Mode:
      • For Google Pixel: Power + Volume Down.
      • For Xiaomi: Power + Volume Down (then select Fastboot).
      • For Samsung: Power + Volume Down + Bixby (mode Download Mode).
  • On the PC, open the command line in the folder with the firmware and enter: 
    fastboot devices

    Make sure that the device is detected.

  • To flash all partitions, use the script (if it is in the archive) or enter commands manually: 
    fastboot flash boot boot.img

    fastboot flash system system.img
    

    fastboot flash vendor vendor.img
    

    fastboot flash dtbo dtbo.img

    (the list of commands depends on the structure of the firmware).

  • After flashing all partitions do: 
    fastboot reboot
    • ⚠️ Attention: On devices Samsung with a chip Exynos (for example, Galaxy S21 Ultra) for firmware via Fastboot a special utility is required Odin. Using standard Fastbootcommands may lead to errors!

    4. Firmware via Odin (only for Samsung)

    Devices Samsung use their own firmware protocol, so for them needed Odin —an official utility from Samsung (available online as Odin3). It supports firmware files in the format .tar or .md5.

    Instructions:

    1. Download Odin (version 3.14.4 or later) and firmware for your model (for example, AP_..., BL_..., CP_..., CSC_...).
    2. Unzip the firmware (usually several files with the extension .tar.md5).
    3. Run Odin as administrator.
    4. Download the device into Download Mode (Power + Volume Down + Bixby).
    5. Connect the smartphone to the PC. In Odin a message should appear Added!!.
    6. Upload the firmware files into the appropriate fields:
      • BL → BL_... (Bootloader).
      • AP → AP_... (System).
      • CP → CP_... (Modem).
      • CSC → CSC_... (Country-Specific Code). select HOME_CSC.
  • Click Start and wait for completion (the process will take 5-15 minutes).
  • After the reboot, the device will be flashed.

    • If Odin gives an error FAIL! with code SW REV CHECK FAIL, which means the firmware version is not compatible with your device. Try downloading another version or check the model matches.

    Table: Comparison of firmware methods

    Method Unlocking required bootloader? Supported file formats Is data saved? Complexity
    Recovery (zip) ❌ No .zip (OTA, custom firmware) ✅ Yes ⭐⭐ (simple)
    ADB Sideload ❌ No .zip ✅ Yes ⭐⭐⭐ (average)
    Fastboot ✅ Yes .img (full partition images) ❌ No (reset) ⭐⭐⭐⭐ (difficult)
    Odin (Samsung) ❌ No (but reset when using CSC) .tar.md5 ⚠️ Partially (depending on CSC) ⭐⭐⭐ (average)

    Typical errors and how to avoid them

    Even when following the instructions, users often encounter problems. Let's look at the most common errors and their solutions.

    1. Error "E: signature verification failed"

    This error occurs if the firmware file is not signed with an official key (typical for custom firmware). Solutions: Recovery, if the firmware file is not signed with an official key (typical for custom firmware). Solutions:

    • 🔧 If the firmware is custom, find a version with signature verification disabled (look for files marked unsigned or no-verity).
    • 🔄 Reflash Recovery to custom (for example, TWRP), which ignores signature verification.
    • 📁 Check the integrity of the file (it may have been downloaded with an error).

    2. The device does not turn on after the firmware ("brick")

    If after the firmware the device does not respond to the power button, does not show the splash screen and is not detected. PC, this is called "hard brick". In most cases, it can be restored, but you will need special equipment (for example, for Samsung or for Qualcomm). What to do: Try holding down the power button for 30-60 seconds (sometimes it helps "soft" brick). USB JIG for Samsung or EDL Mode for Qualcomm).

    What to do:

    • 🔌 Try holding the power button for 30-60 seconds (sometimes it helps with a “soft” brick).
    • 🖥️ Connect to the PC and check whether the device is detected in Fastboot or Download Mode. If so, repeat the firmware.
    • 🛠️ For Qualcommdevices: try to log into EDL Mode (usually by shorting the contacts on the board) and flash through QFil or Mi Flash.
    • 📞 Contact the service center if self-recovery fails.

    3. Error "Invalid". IMEI" or loss of network after flashing

    This problem occurs if, when flashing via Fastboot or Odin partitions modem (CP) or EFS (where the IMEI). Solutions:

    • 📡 Reflash only the partition modem (file CP_...tar.md5 in Odin or vendor/radio.img in Fastboot).
    • 🔢 Restore the backup copy of the partition EFS (if you made a backup before the firmware).
    • 📞 For Samsung: use the utility Samsung Tool PRO to restore IMEI.

    If IMEI is lost irrevocably, it is impossible to restore it yourself - you will need to contact a service center with proof of purchase of the device.

    4. Stuck on the logo after flashing the firmware ("bootloop")

    If the device turns on, but constantly reboots on the logo, the reason is usually:

    • 🔄 Incompatibility of the firmware with the model device.
    • 🗃️ Partition damage system or boot.
    • 🔧 Lack of wipe (cleaning) before installing custom firmware.

    Solutions:

    • 🔄 Repeat the firmware, first running Wipe Data/Factory Reset v Recovery.
    • 📁 Reflash only the partition boot (if the problem is in it).
    • 🔧 Install a different version of the firmware (the current one may contain bugs).
    💡

    If after updating the device the device gets hot, discharges quickly or slows down, reset to factory settings via Recovery. Often this solves problems with optimizing the system after the update.

    How to roll back to the previous version. Android

    A rollback to the old firmware may be necessary if the new update contains critical bugs, is slow or does not support the functions you need. However, this process has nuances:

    • 🔙 On most devices, a rollback is only possible through full firmware (not via OTA).
    • 🔒 On some models (for example, Google Pixel) rollback is blocked by the function Anti-Rollback.
    • 📵 Rollback can lead to data loss if you do not make a backup in advance.

    Instructions for rollback:

    1. Find the official firmware of the old version for your model (for example, on Sammobile or Xiaomi Firmware Updater).
    2. Reset to factory settings (Wipe Data on Recovery).
    3. Flash the old version using the selected method (Odin, Fastboot or Recovery).
    4. If the device is not turns on, try flashing only the partition boot or system (without userdata).
    ⚠️ Attention: On devices with Dynamic Partitions (Android 10+), rolling back to older versions may lead to data loss in the partition userdata, even if you do not performed wipe. Always make a backup copy!

    FAQ: Frequently asked questions about local updates

    Is it possible to install firmware from another model?

    No, this will lead to the "briku" device. The firmware must correspond to the exact model (for example, SM-G973F for Galaxy S10 and SM-G973U for the American version - these are different devices!), with the exception of some custom firmware (for example, LineageOS). which support several models.

    Why did photos and applications disappear after the firmware?

    If you performed Wipe Data or flashed the full image via Fastboot/Odin, user data (/data partition) have been erased. You can only restore them from a backup. In the future, use HOME_CSC v Odin or --disable-verity v Fastbootto save the data.

    How to check Is the bootloader unlocked?

    Turn off the device and boot into Fastboot Mode. If you see the message Device State: Unlocked, it means bootloader unlocked. If Locked — unlocking will be required for the firmware. via Fastboot. On some devices (for example, Huawei) unlocking requires an official code from the manufacturer.

    Is it possible to flash a custom Recovery (TWRP) without unlocking the bootloader?

    No, installation TWRP or another custom Recovery requires unlocked bootloader. The exception is some old devices (for example Samsung Galaxy S5), where Recovery can be flashed through Odin without complete unlocking.

    What to do if Touch ID or Face Unlock does not work after flashing?

    This is typical problem when downgrading to an older version of Android or flashing unofficial builds. Biometric data is stored in a secure partition, which can be damaged. Solutions:

    1. Reflash the partition persist (if it is in your firmware).
    2. Perform a full reset and set up the biometrics again.
    3. If the problem persists, install the official firmware via Odin/Fastboot.
    💡

    Before any firmware, check the MD5 hash of the downloaded file - this ensures that the file is not damaged. The hash can be checked with utilities like 7-Zip or MD5 Checker.