The following tutorial demonstrates how to enter Bootloader Mode on each different Android manufacturer.
What is Bootloader Mode
The bootloader is the program that boots the Android operating system. Sometimes you may wish to be in the environment called Bootloader Mode so you can perform certain tasks that you couldn’t do from the operating system itself, such as when running ADB commands capable of performing tasks such as flashing new boot images. Bootloader Mode is similar to Recovery Mode in that they are different environments to the OS itself.
Most popular smartphone manufacturers that choose to run Android as the operating system have different methods for getting their devices into Bootloader Mode. But thankfully they all have methods using hardware keys directly on the device; only the key combination itself is what changes.
Here are the different key combinations you need to get into Bootloader Mode:
How to Enter Android Bootloader Mode for Each Manufacturer
HTC Smartphones: Press and hold the Volume Down button and then press the Power button while still keeping the Volume Down button pressed. HTC refers to the Bootloader Mode as Fastboot Mode (due to the assumption people will be running fastboot commands).
LG Smartphones: Press and hold Power and Volume Down and release them when the LG logo appears on the smartphone’s display. Alternatively, only release them for a second and then press them again a second time to get Bootloader Mode to appear.
Motorola Smartphones: Press and hold the Power and Volume Down buttons simultaneously for a few seconds and then release them both at the same time.
Samsung Smartphones: Samsung doesn’t have a Bootloader Mode but instead replaces it with a Download Mode that is compatible with their proprietary flashing tool, Odin. Download Mode can be accessed by pressing the Power + Volume Down + Home buttons simultaneously until the Samsung logo appears.
Nexus and Developer Smartphones: Press and hold Power and Volume Down until the Google splash screen appears and then release them.
In conclusion, that is how to enter Android’s Bootloader Mode for each manufacturer.