What is Bootloader, what are its possible causes and solutions

Today we are going to talk about a problem that does not happen very often, but that may be happening to you right now: we are talking about the bootloader. In this article I want to explain what bootloader is, what are its possible causes and its possible solutions.

And it is that, although Android is one of the most stable mobile operating systems, it still has bugs or bricks that could jeopardize your mobile.

What is bootloader

It is a problem that has very varied causes and that consists of the constant restart of the mobile.

When this problem occurs on the mobile device, it will not load the operating system and the boot process will end when the manufacturer’s logo appears on the screen.

The above will be repeated indefinitely in case we are facing a boot-loop error. It will look similar to the following image.

Possible causes of a bootloader on your mobile

Although a bootloader can occur for several reasons, the causes that can generally give rise to these types of problems are usually the following:

  • Modifications of our device: If we use root applications to modify the system or install a custom ROM and touch something we shouldn’t, our device will suffer a bootloader.
  • A system update is also usually a common cause of bootloader: Sometimes an interrupted update can cause this problem.

Possible solutions

If you are faced with this type of problem, you should not necessarily leave your mobile phone behind and go out and buy another one immediately.

Let us now with some possible solutions for your problem. Please try before you give up on your device.

Solution 1: contact the manufacturer

If the bootloader started without you trying to modify it and your phone is still under warranty, you can try as a first option to contact the company that sold you the phone or the manufacturer.

This is an almost sure way to solve the problem, but it will keep you without your mobile phone for a while, while the relevant reviews are done.

Remember that you have to verify that the error was not caused by you, in addition to all the bureaucracy and bad intentions that some companies bring.

If you don’t want the long option, then read solution number two, Let’s go!

Solution 2: dip into the recovery mode

The recovery mode or recovery mode is a restoration or recovery tool that all Android phones bring.

Through this tool we can restore our phone to its factory state, this is possible even if it cannot start the operating system.

A problem with using this tool is that all the data and settings of your mobile will be lost.

How to access the recovery mode

To access we must use a key combination. Usually, we can do it by pressing the button power + volume down button.

If this does not work, you should find the key combination that the manufacturer of your mobile has established. For this, you can search Google in the following way: name of your phone + recovery mode.

I leave you a list of how to enter the recovery mode of some manufacturers. Courtesy of Androidpit

Once in the recovery mode, we will have to choose the factory reset option and wait for the phone to be restored to its factory settings.

Use the recovery model of a mobile with a custom ROM

The process to access the recovery is the same, but surely you will find recovery with more options than in the previous case.

With this personalized Recovery, you can perform a Wipe All / Factory Reset, install a new ROM or restore a backup that you have previously created.

Solution 3: using the factory image

This is the most radical and most tedious option. It is about searching the internet for the original image of our operating system and installing it ourselves through our computer.

A factory image is a file in which the complete system is located and that we can transfer to our device to restore it.

It is more tedious because each model of mobile has its own program to install the image of the operating system and its own image, and the process takes a bit.

We will also need our mobile to be in mode download or fastboot. This mode allows us to make files or data transfers from the computer to the mobile.

The good thing is that with this method we can restore our operating system completely. Let’s see how the process is.

Steps and prior recommendations before downloading and installing factory image (stock ROM) using Fastboot.

Note: If you were curious about the term stock ROM, you can learn more about it in our article: What is a ROM, what is its function and what types exist.

Now, let’s continue with the previous recommendations:

  • Make sure you have installed the USB drivers or mediatek mtk driver auto installer. This will depend on the model of your device. This way you can connect your device to the computer correctly.
  • Battery greater than 60% to prevent it from turning off during the process.
  • Activate the depuration USB and the developer options on your Android device. It also enables the OEM unlock, if the option is available.
  • So you can continue this guide on how to download and install a factory image (stock ROM) using Fastboot, you must unlock bootloader (bootloader) of the mobile.

    When you unlock it you will lose all the personal data stored in it. So, I recommend you do a backup using TWRP.

Steps and files needed to download and install factory image (stock ROM) using Fastboot.

Considering the above, we now go to the heart of the matter. We will start by installing ADB and Fastboot.

  • Download the factory image according to your device: for this step you must do a Google search as follows «Your device name + the word factory image».

Install factory image using fastboot

Step 1

In a blank space inside the folder (C: adb), press the key shift + right click on the mouse and then choose the option that says open command window here.

What is Bootloop, what are its possible causes and solutions

Step 2

Connect the device with the computer using the USB cable. Restart the device in bootloader mode.

Step 3

Move all the contents of the downloaded ROM to the C: adb folder and in the command window type the following line fastboot flash-all, then press Enter.

The process takes a few minutes to finish. Then your mobile will restart.


In the event that the downloaded ROM does not have the flash-all file, which is in charge of flashing or installing each of the files, the previous option would not serve us.

This being the case, we must flash each of the files separately.

Flashing stock ROM without flash-all file

Step 1

We start by installing the boot image. We type in console fastboot flash boot «boot image file name».

Step 2

Then flash the bootloader imageand: To flash the bootloader, type fastboot on the command line flash bootloader «bootloader image filename».

Step 3

Then type the following command and hit Enter: fastboot reboot-bootloader.

Step 4

Now flash the radio image. This image is in charge of the connectivity on your mobile. To do this, type the following command and press Enter: fastboot flash radio “radio image file name”.

Step # 5

At this point you can flash the recovery. This is optional, depending on the modifications you have made.

If you have previously installed the TWRP recovery this image will overwrite the TWRP and replace it with the original recovery interface. To flash the recovery type the following command and press Enter: fastboot flash recovery “file name recovery”.

Step # 6

Now you must flash the operating system image. This contains all the files that make up the Android operating system.

It is the primary part of any update and is the element that will solve our Boot-loop problem.

To flash the system image, type the following command and press Enter: fastboot flash system “system file name”.

Last step

Finally, flash the manufacturer’s image. This is only present in the latest mobiles. We can install it by writing the following: fastboot flash vendor “manufacturer name”.

Now restart your mobile and type the following command, then press Enter: fastboot reboot.

We have finished for today

I hope that for you things are clearer regarding what a bootloader is and that you have been able to solve it.

At Doctor Xiaomi, we know that there are few things sadder than seeing your mobile phone dying without knowing what to do to help it.

And speaking of help … do you want to say something about what bootloader is or do you have any other possible solution? You already know that the comment box is all yours. We are reading 😉.