Your Android smartphone won't turn on? There could be many causes, starting with a hardware, software or firmware error. The purpose of this article is to attempt to explain how to diagnose boot problems of an unmodified Android device and how to fix them.
It may be that something went wrong when you tried to update your smartphone to the latest version of Android. got stuck in a boot-loop. In an online search, you found that you need to flash a new ROM.
However, the software for flashing the ROM on the computer cannot see the phone, although it may be recognized (like an Android phone) within the Windows Device Manager. At this point I ask myself: is there a way to repair my phone or do I have to look for a new ROM?
The main purpose of this guide is not to deal with the method of installing custom ROMs. There are too many variables that could cause damage to the phone. Instead we want to study the symptoms of the different devices when it is not possible to turn on the display and how to solve these problems.
What to do if an Android smartphone does not turn on?
When an Android smartphone or tablet freezes on startup, there are two questions you need to ask yourself: a hardware or software problem (for simplicity I considered software and firmware in the same category)?
A successful diagnosis requires good observation. Does the Android device do something out of the ordinary? And what did you do with the device before it started? The answer to both questions can solve, or explain, the startup error.
A device when it does not start can be classified into four different categories:
- Not bootable Scenario 1: No charging light, not hot after charging, it is not detected by the computer after connecting it to it, no Android boot screen;
- Unbootable Scenario 2: the charging light turns on, it is detected after connecting it to the desktop or laptop, no Android startup screen.
- Unbootable Scenario 3: the startup screen is continuously displayed cyclically, the system freezes or restarts continuously;
- Unbootable Scenario 4: The system does not start and displays an error message on a black screen;
Before fixing the problem, we need to explain the various tools and tricks available to Android users:
What are the tools to recover an Android smartphone?
There are a number of tools to fix Android startup problems. Here are the most common:
- Bootloader (or recovery) factory reset;
- Bootloader (or recovery) clean the cache;
- The recovery toolkit software;
- Android safe mode;
- removable battery;
- soft and hard reboots;
How to use an Android Bootloader?
A bootloader allows users to load different bootable portions (or partitions) of the operating system. It allows users to select between starting a recovery partition or their operating system. When the operating system cannot be started, the bootloader can restore the original operating system.
The manufacturers also include options within the recovery or bootloader to clean the device cache. Cleaning up a damaged cache can also solve boot problems. However, each device manufacturer differs in the type of tools and functions that it makes available within the pre-boot environment (or bootloader).
Here is an example of how the bootloader looks on a Moto X 2014:
As you can see, there are several options available. The most relevant (on an unmodified device): Factory or the Factory Reset option.
Factory Reset of an unbootable Android device
The most common method is to turn off the device, so hold down the power button + volume Gi. While holding the keys, wait for the device to vibrate gently and enter the Android bootloader (or recovery). Note: Some manufacturers use the volume up key instead of volume Gi.
Again they differ from manufacturer to manufacturer, but most include all the same basic features.
Select Factory Reset using the volume keys to scroll and the power key to select an option. The device then initiates a factory reset by installing the original system. The device should reboot and begin a long re-initialization process. However, if you have installed a custom ROM, exercise extreme caution or you will not be able to use the recovery or bootloader to start the factory reset process. In general, if the system has been modified, perform a factory reset from the custom recovery.
Also keep in mind that the volume keys don't always work as directional keys. On Motorola phones, the Up volume button selects an option and the Gi volume scrolls through the options.
Access variations to the Bootloader
To my knowledge, there are four different types of key combinations that allow users to load the bootloader. You must perform these key combinations from the off state:
Power button + Volume Up Power button + Volume Gi Power button + volume up + volume gi The Samsung method (see below)
If you find it difficult to locate the bootloader, keep in mind that not all manufacturers refer to the bootloader name. Some (especially Samsung) refer to it with a commercial name (although Android includes its own version of Download Mode). In this case you have to look for the factory reset option. If in doubt, use a search engine.
Some devices allow factory reset by simply touching the buttons during startup. Others require starting the bootloader.
Samsung Download Mode
Unfortunately, many of the major device manufacturers use different methods of reaching the bootloader (or other modes). Samsung calls the pre-boot recovery environment like Download mode. Since Samsung devices can include a physical home button, they sometimes use this as a means of accessing the pre-boot environment.
Due to the big difference of Samsung devices, you need to search the Internet on how to access the Download Mode of your smartphone model.
How to use Android Bootloader or Recovery to clear cache?
Another option to solve the problem if the Android smartphone does not turn on, resides within the Android pre-boot environment. Most manufacturers include an option to delete the cache partition within the recovery, but the bootloader also has this feature. There are two types of cache: the Dalvik cache or the system cache. Android 5.0 and above only include the system cache.
To clear the cache, start the Android bootloader and select the recovery option.
Some manufacturers, at this point, require pressing additional keys in order to clear the cache partition. For example, the Moto X prompts you to hold down the power button + volume down.
Then select wipe cache partition. When it finishes cleaning the cache, restart.
How to use a recovery toolkit software and other options?
If your Android smartphone won't turn on, recovery toolkits exist that vary from manufacturer to manufacturer. Nexus devices have access to several variations, such as Samsungs Kies. Other software tools include Minimal Fastboot. Check what is right for you.