Android updates are not just new features, but also vulnerability fixes, performance optimizations, and support for new applications. However, many users are faced with a situation where the update stuck at the download stage, not installed or disappears after a reboot. To understand the problem, you need to know where exactly the update files are stored on the device, how to find them and what to do if the process does not go according to plan.

In this article We will take a detailed look at all the possible paths by which updates are downloaded and saved - from standard folders in the phone’s memory to hidden system sections. You will learn how to access the firmware files (OTA and full ROM), what tools you will need for this, and what to do if the update is stuck in the "99% download" status and does not move further. We will also figure out whether it is possible to manually transfer the update from a PC to a phone and how to avoid errors during installation.

1. Standard paths for storing updates on Android

By default, Android update files are stored in protected sections of the system, but some of them are accessible to the user. The main places where you can find downloaded firmware:

  • 📁 Folder /cache —temporary update files (OTA) are stored here, which are automatically deleted after installation. It can only be accessed through ADB or recovery.
  • 📁 Folder /data/ota_package —used on some devices (for example, Xiaomi, Realme) to store downloaded updates until they are installed.
  • 📁 Folder Download in the internal memory — if the update was downloaded manually through a browser or proprietary software (for example, Samsung Smart Switch or Huawei HiSuite).
  • 📁 Hidden section /firmware or /system/update —here are the full firmware files (full ROM), but access to them requires root access.

On devices with pure Android (for example, Google Pixel) updates are usually downloaded to the folder /cache and installed immediately without saving a copy. On custom shells (for example, MIUI, One UI, ColorOS) files can remain in memory until rebooted.

📊 How often do you update? firmware on your smartphone?
As soon as a new version comes out
Every six months
Only if problems arise
I never update

If there is an update stuck at the loading stage, it the file may remain in one of these folders. To find it, you will need file manager with superuser rights (for example, Root Explorer or FX File Explorer) or connecting to the PC via ADB.

⚠️ Attention: Deleting files from folders /cache or /data/ota_package may cause the current update process to fail. If the system has already started the installation, do not forcefully interrupt it - this may result in brick (complete inoperability) of the device.

2. How to find the update file through the file manager

If you want to manually check whether the update has been downloaded, or are trying to install it again, follow these instructions:

  1. Open file manager (for example Files by Google, Total Commander or built into the shell).
  2. Go to the root directory of the internal memory (not the SD card!).
  3. Check the following folders:
    • 🔍 Download — there may be files with the extension .zip (for example, update.zip).
    • 🔍 MIUI → download (on Xiaomi).
    • 🔍 OTA or fota (on Samsung, Huawei).
  • If the file is not there, try turning on display hidden folders in the settings manager.

    • Update files usually have the following names:

    • 📄 update.zip —standard name for manual firmware.
    • 📄 OTA_*.zip —automatic over-the-air updates.
    • 📄 BL_*.img, AP_*.tar —components of complete firmware (for example, for Samsung Odin).

    ☑️ Search for update file

    Done: 0 / 4

    On some devices (for example, OnePlus or Oppo) update files are encrypted and stored in private sections. In this case, they can only be retrieved via ADB or special utilities from the manufacturer.

    3. Where updates are stored on the PC when downloaded through proprietary software

    If you update the phone via a computer (for example, using Samsung Smart Switch, Xiaomi Mi Flash or LG Bridge), the firmware files are saved on the hard drive PC disk. Their paths depend on the app:

    app Storage path File type
    Samsung Smart Switch C:\Users\[User_name]\Documents\Samsung\SmartSwitch\ .enc4, .md5
    Xiaomi Mi Flash C:\Xiaomi\Flash\ or user-selected folder .tgz, .zip
    Huawei HiSuite C:\Users\[Username]\AppData\Local\HiSuite\ .app, .zip
    LG Bridge C:\ProgramData\LGMOBILEAX\Phone\ .kdz, .dz

    These files can be copied to the phone for manual installation, but please note:

    • 🔄 Firmware for PC is often weigh 1–3 GB and take up a lot of space.
    • 🔄 Not all files are suitable for installation via recovery —some require proprietary utilities.
    • 🔄 You can rename files (for example, to update.zip) only if this is expressly stated in the manufacturer's instructions.
    ⚠️ Attention: If you downloaded the firmware via Samsung Smart Switch, you cannot simply transfer it to your phone and install it via recovery. proprietary format .enc4 and require decryption with special tools (for example, Frija or SamFirm).

    4. How to check if the update has been downloaded via ADB

    If the update file is not visible in the standard manager, it can be found through Android Debug Bridge (ADB). This method works even without root access, but requires enabled debugging USB.

    Instructions:

    1. Connect your phone to the PC and enable debugging (a pop-up window on the phone screen).
    2. Open command line (Windows) or terminal (macOS/Linux) in the folder with ADB.
    3. Run the command to search for update files: 
      adb shell ls /cache/

      or

      adb shell ls /data/ota_package/
    4. If the file is found, copy it to your PC for backup: 
      adb pull /cache/update.zip C:\backup\

    Typical file names that are worth looking for:

    • 📄 cm-*.zip — for LineageOS and custom firmware.
    • 📄 ota_update_*.zip — for stock ROM (original firmware).
    • 📄 payload.bin — update format for Google Pixel and some other devices.
    💡

    If the command adb shell ls does not show files in /cache, try rebooting the phone in recovery i repeat the command. In some cases, files become visible only after a reboot.

    If you find a file, but are not sure what to do with it next, do not delete it it may be needed to restore the system in case of a failure.

    5. What to do if the update is stuck at 99% or is not installed

    One of the most common problems is updating hangs at the loading stage (for example, 99%) or cannot install due to an error. In this case, the firmware file may remain in the phone's memory. but the system “doesn’t see it.” Here’s what you can do:

    • 🔄 Restart your phone - sometimes this helps to resume the process.
    • 🔄 Clear the update cache:
      1. Go to Settings → Applications → All applications.
      2. Find Software Update Service (or Software Update).
      3. Click Clear cache and Stop.
    • 🔄 Delete the downloaded file manually (if it is damaged): 
      adb shell rm /cache/update.zip
    • 🔄 Try installing the update through recovery:
      1. Download the firmware again from the official website.
      2. Place it in the root of the internal memory (for example, update.zip).
      3. Press Power + Volume Up to enter recovery.
      4. Select Apply update from ADB or Install from storage.
    ⚠️ Attention: If when installing via recovery error E:footer is wrong or E:signature verification failedappears, this means that the firmware file is damaged or not intended for your model. Do not try to install it forcibly - this can lead to brik devices.
    What to do if the phone does not turn on after the update fails?

    If the device does not responds to the power button, try holding down the combination for hard reset (For example, Power + Volume Down for 10-15 seconds). If this does not help, you will need to flash it through fastboot or a service center.

    6. How to manually transfer the update from your PC to your phone.

    If automatic update download does not work (for example, due to slow Internet or server errors), you can download the firmware on your PC and transfer it to your phone. To do this:

    1. Find official firmware for your model on the manufacturer's website:
  • Download the file (usually this .zip or .tgz).
  • Connect the phone to the PC and transfer the file to root of the internal memory (not to folders!).
  • Turn off the phone and go to recovery (the combination of buttons depends on the model).
  • Select Apply update from storage and specify the downloaded file.

    • Important nuances:

    • 🔄 The file name must be without Cyrillic and spaces (for example, update.zip).
    • 🔄 For Samsung often required four-file firmware (AP, BL, CP, CSC), which is flashed through Odin.
    • 🔄 On Google Pixel updates in format payload.bin need to be unpacked using Payload Dumper.
    💡

    Installing firmware through recovery erases user data only if you select the option Wipe data/factory reset. Without this, the data remains intact, but the risk of failure is higher.

    7. Why the update may disappear after a reboot

    Sometimes users encounter a situation where update downloaded, but disappeared after reboot or the system “does not see it”. Reasons and solutions:

    Problem Cause Solution
    The file disappeared from the folder Download The system automatically cleared the cache Disable automatic clearing in the memory settings
    The update is not installed after downloading The file is damaged or incompatible with the version bootloader Download the firmware again from the official source
    The download process starts again The manufacturer's server reset the session Use a VPN or download the firmware on a PC
    The phone does not find the file in recovery Incorrect file name or path Place the file in the root of memory and rename it to update.zip

    On some devices (for example, Huawei or Honor) updates are stored in protected section will help., which is cleared upon reboot. In this case, only re-downloading or installation via a HiSuite.

    8. Security: risks when manually installing updates.

    Installing firmware manually is a powerful tool, but it is fraught with risks. The main dangers and how to avoid them:

    • 🚨 Brick devices - if the firmware is not intended for your model or region (CSCAlways check the compatibility by model number (you can find it in Settings → About phone).
    • 🚨 Data loss —even if you do not select Wipe data, a failure with the firmware can damage the partition /dataMake a backup via TWRP or ADB Backup.
    • 🚨 Data leak —download firmware only from official sources. Files from torrents or unverified sites may contain malicious code.
    • 🚨 Locking the bootloader —on some devices (for example, Sony Xperia), unofficial firmware can block the bootloader, making the phone inoperable.

    Before installation check:

    1. Is device model (for example, SM-G973F for Samsung Galaxy S10).
    2. Is bootloader version suitable (for example, BL: G973FXXU3ATD1).
    3. Are there marks in the file name like userdata or home_binary —they erase data.
    ⚠️ Attention: On devices with a locked bootloader (for example, most Samsung or Motorola) installation of unofficial firmware will lead to hard brick. Before installing the firmware, check the status of the bootloader with the command: 
    adb reboot bootloader

    fastboot oem device-info

    If there is Device unlocked: false, unlock the bootloader in the official way.

    FAQ: Frequently asked questions about Android update files

    Is it possible to cancel the download of an update if it has already started?

    Yes, but the method depends on the stage:

    • If the download is in progress via Settings → Software update, you can press Cancel or restart the phone.
    • If the file has already been downloaded but not installed, delete it via ADB or a file manager (see section 4).

    If an update already being installed (the process is in progress on the screen with a progress bar), you cannot interrupt it - this will lead to a system failure.

    Why does the update weigh 2 GB, but it is not in the Download folder?

    Most likely, the file is downloaded from hidden section (for example, /cache or /data/ota_packageAlso some manufacturers (for example, Samsung) divide the firmware into parts and download them separately, so you will not see one large file.

    To check the occupied space, use ADB: 

    adb shell df -h /cache

    Is it possible to install an update from another region?

    Technically yes, but this is fraught with problems:

    • Could stop working mobile communications, Wi-Fi or camera (due to different modules).
    • Some applications (for example, Samsung Pay or Google Wallet) will refuse to work.
    • Over-the-air updates (OTA) will no longer arrive.

    If you want to flash the firmware of another region, choose the one that matches CSC (for example, SER for Russia or XEF for France).

    What to do if after the update the phone starts to slow down?

    Try the following steps:

    1. Clean system cache via recovery (Wipe cache partition).
    2. Disable animations and transitions in the developer settings (Settings → About phone → Build number - tap 7 times).
    3. Check if the processor is overheating (use CPU Monitor or AIDA64).
    4. If all else fails, run factory reset (but make a backup copy first!).
    How do I know which firmware is suitable for my phone?

    Check the following parameters:

    1. Device model: Settings → About phone → Model (for example, RMX3363 for Realme 9 Pro).
    2. Current firmware version: Settings → About phone → MIUI/One UI/EMUI version.
    3. Region (CSC): you can find out through ADB: 
      adb shell getprop ro.csc.countryiso

    Download the firmware only from official sources, indicating all this data. For example, for Samsung you need Model, CSC i PDA.