The process of updating or flashing the Android operating system is one of the most common procedures faced by users of modern smartphones. The question of how long it takes to flash Android firmware does not have a single universal answer, since the duration of the process varies widely. Depending on the method chosen, the device model and the amount of data being installed, this procedure can take from 5-10 minutes with an automatic update over the air to 1.5-2 hours with a complete manual installation via a computer.
Understanding the time costs is critical for proper planning: you must make sure that you will not need the device during this period of time, and that the battery charge will be sufficient to complete all stages. Interrupting the process halfway due to lack of time or energy can lead to serious software glitches that turn the phone into a brick. Therefore, before starting any manipulations with the system partition, it is necessary to soberly assess the current state of the gadget and available resources.
In this article we will analyze in detail the factors affecting the speed of software installation, compare different update methods and give real time frames for different scenarios. You will find out why installation via Recovery is sometimes slower than via PC, and what steps are the “bottleneck” in the process of installing a new version of the system.
Factors influencing the speed of system installation
The first and most significant factor determining the duration of the process is type of method used updates. Automatic OTA (Over-The-Air) updates that come directly to the phone usually take less time, since the system only downloads the delta - the difference between the old and new version. At the same time, a complete flashing via a computer using utilities like Odin for Samsung or SP Flash Tool for MediaTek requires writing all memory sections anew, which significantly increases time costs.
The second important aspect is technical characteristics of the smartphone itself. The speed of writing data to internal memory (eMMC or UFS) directly affects how quickly the archive with the firmware is unpacked and installed. Flagship models with UFS 3.1 or 4.0 memory cope with this task many times faster than budget devices, where the write speed can be limited by the physical capabilities of the drive.
Use the original USB cable and USB 3.0 port on your computer for maximum data transfer speed when flashing manually. Cheap cables often limit the speed and can cause connection errors.
Also (not to be ignored) is the amount of data being installed. If you perform a factory reset before installing a new system, the process will take longer due to the need to format partitions and then initially set up the system. Having a large amount of user data that the system tries to save or migrate in the background (with OTA) can also slow down the final stage of application optimization.
Over-the-air (OTA) update time
Updating “over the air” is the simplest and least labor-intensive method for the average user. The whole process can be divided into three logical stages: downloading the package, preparation and direct installation. The download depends solely on the speed of your Internet connection and the file size, which usually ranges from 500 MB to 3 GB for major Android version updates.
The installation itself occurs after the device restarts and displays the system logo or robot animation. At this stage, the phone applies the received packets to the system partitions. For most modern devices, this phase takes from 5 to 15 minutes. However, on older models or when switching between major versions (for example, from Android 12 to 13), the application optimization process may take another 10–20 minutes after the first start.
⚠️ Attention: If the update screen is stuck in one place for more than 30 minutes, do not immediately panic. Sometimes the progress bar does not update visually even though the recording process is in progress. However, if the phone is hot and the screen is black for more than an hour, a force reboot may be required.
It is worth noting that during the OTA installation, the user cannot use the phone. It is recommended to run this process before going to bed or at a time when the gadget is definitely not needed for calls or work. The stability of the Wi-Fi connection also plays a role: if the download is interrupted by 90%, the system will have to start downloading again or download damaged segments, which will increase the overall waiting time.
Duration of manual firmware via a computer
Manual firmware via a PC is a more complex method that is often used when restoring non-working devices or installing custom firmware. Here, time consists of preparation, recording process and post-production. The preparatory stage, which includes installing drivers ADB, searching for the required firmware image and switching the phone to Download Mode or Fastboot, can take from 15 to 40 minutes for an unprepared user.
The direct process of writing an image to the device memory through the interface of flashing apps usually lasts longer than OTA. This is due to the fact that all sections are recorded as a whole: boot, system, recovery, vendor and others. On average, recording a complete image on a modern smartphone takes from 20 to 45 minutes. The speed depends on the bandwidth of the USB port and the read/write speed of the phone's flash memory.
☑️ Check before manual firmware
After recording is completed, the device will automatically reboot. The first startup after manual firmware always takes longer than usual. The system checks the integrity of files, recreates the Dalvik/ART cache and optimizes all installed applications for the new environment. This stage, known as “Android is upgrading,” can take from 5 to 15 minutes depending on the number of installed apps.
Features of firmware via Recovery Mode
Installing updates via the recovery menu (Recovery Mode) occupies an intermediate position in time between OTA and full firmware from a PC. This method is often used to install official updates manually (via a .zip file on a memory card) or to install custom builds. The process begins by selecting a file from the Apply update from SD card or Apply update from ADB.
menu. The installation time here is comparable to an OTA update, since the same differential update mechanisms are often used. However, if you install the full firmware as a ZIP archive via Recovery, the time may increase to 20–30 minutes due to the need to verify the digital signature and unpack the archive directly on the device before recording.
It is important to consider that some custom Recovery, such as TWRP, have their own interface and operating logic, which may differ slightly in speed from stock recovery. In addition, cleaning partitions (Wipe), which is often recommended to be done before installing new firmware in Recovery, adds another 2-5 minutes to the total time, depending on the amount of filled memory.
Why is the first startup after the firmware so long?
After updating the system, Android must recompile the optimized code of all installed applications (.odex/.vdex files) for the new version runtime. This guarantees stable operation of apps, but requires significant processor resources and time.
Comparative table of firmware time
For clarity, we present average data on the time required for various update scenarios on devices in the middle and high price segment. Please note that these values may vary depending on the specific model and condition of the drive.
| Update method | Preparation | Installation (writing) | First run | Total time |
|---|---|---|---|---|
| OTA (by air) | 5-10 min (download) | 5-15 min | 5-10 min | 15-35 min |
| Via PC (full) | 20-40 min | 20-45 min | 10-15 min | 50-100 min |
| Via Recovery (ZIP) | 10-15 min | 10-25 min | 5-15 min | 25-55 min |
| Recovery (Unbrick) | 30-60 min | 30-60 min | 10-20 min | 70-140 min |
As can be seen from the table, the most time-consuming method is the recovery method via a computer, especially if preliminary setup of the environment and search for specific firmware files are required. The fastest way is standard OTA, but it is only available if the system is working and there is an official update from the manufacturer.
The application optimization stage and its impact
One of the most annoying moments for users is the screen with the words “Application optimization” or “Android is upgrading” that appears after the update. Many people mistakenly believe that at this moment the system is being installed, but in fact the firmware itself has already been recorded. Now the system is bringing its internal databases into line with the new version of the kernel and libraries.
The duration of this stage directly depends on the number of applications you have installed. If your smartphone has 50–100 apps installed, the process may take 5–7 minutes. If there are several hundred applications, especially heavy games and specialized software, the optimization time can stretch to 20 minutes or more. It is highly undesirable to interrupt this process, as this can lead to a cyclic reboot.
⚠️ Attention: Do not try to speed up this stage by forcing a reboot. If optimization is stuck on one application for more than 10 minutes, the file of this application may be damaged and conflicts with the new system.
In some cases, especially when switching to custom firmware, the system may offer to clear application data (Wipe Data). If you agree to this, the optimization stage will go faster, since there will be no applications left to process, but you will lose all user settings and data inside the apps.
The total firmware time is the sum of the loading time, data recording and mandatory application optimization. The longest stage with a large number of apps is optimization after the first start.
Possible problems and process delays
Sometimes the firmware process takes an abnormally long time or stops altogether. This may be due to a corrupted firmware file that the system is trying to read repeatedly, encountering checksum errors. Also, the cause of delays is often the overheating of the device: modern smartphones have protection that throttles (reduces) the speed of the processor and recording at high temperatures to avoid physical damage.
Problems with the USB port or cable when connecting to a computer also lead to significant delays. If the connection is unstable, the firmware app may constantly try to resend (resend) data packets, which increases the installation time significantly. In such cases, it is often easier to replace the cable or switch to a different port than to wait for an unsuccessful attempt to complete.
If you are using an older device with worn out flash memory, write speeds may drop to critically low values. Memory blocks that have high wear and tear require multiple recording attempts to save data, which significantly extends the procedure time frame compared to a new phone.
⚠️ Attention: Menu interfaces and item names may differ depending on the version of Android and the manufacturer’s shell (MIUI, OneUI, ColorOS). Always check the official documentation for your specific model before proceeding.
Frequently asked questions (FAQ)
Is it possible to use the phone while flashing the firmware?
No, this is absolutely impossible. During the installation process, the system has full control of the device, the screen is occupied by a progress bar, and touch input is disabled. An attempt to interrupt the process by pressing buttons may damage the bootloader.
What to do if the firmware has been downloading for more than 2 hours?
If the progress indicator does not move for more than 2 hours, the process is most likely frozen. In the case of OTA or Recovery, you can try to force a reboot (by holding down the power and volume buttons). When flashing firmware via a PC, you should check the app logs for errors and try to reconnect the cable.
Does an unlocked bootloader affect the speed of the firmware?
The unlocked bootloader itself does not slow down the process of writing data. However, devices with an unlocked bootloader are often used to install custom firmware, which may be less optimized than the official firmware, which can indirectly affect the first launch and optimization time.
Do you need to remove the SIM card before flashing the firmware?
This is not a strict requirement, but is recommended as a precaution. In rare cases, when resetting settings or firmware errors, conflicts with the operator’s profile may arise, so removing the SIM card will not be unnecessary.
Why does the phone work slower after updating the firmware?
In the first hours after the update, the system actively indexes files, updates databases and optimizes applications in the background. This creates a load on the processor. Typically, performance returns to normal after 24–48 hours of active use.