To install custom software (like LineageOS) or "root" the device. This often requires downloading specific USB Drivers and the ADB & Fastboot toolset.

If a phone won't start, you download a "bootloader image" to repair the start-up code. 3. Essential Tools to Download

Users typically look for downloads related to the bootloader for three main reasons:

The bootloader is the first piece of code that runs when you turn on your phone. it tells the hardware how to start the operating system (Android). By default, most manufacturers "lock" the bootloader to ensure only their official software can run, which protects your security. 2. Why do people "download" for it?

Typically uses a tool called Odin instead of standard fastboot. General Tools: Android SDK Platform-Tools