Most Android devices come with locked bootloaders – i.e., you can’t alter what it does. Bootloader – When you power on a device, the first thing that turns on is the bootloader, which is responsible for starting up other processes.Flashing – When you overwrite one piece of software with another piece of software, that’s called “flashing.” This guide you’re reading goes over how to “flash” LineageOS.
LineageOS will often be referred to as a “ custom ROM,” as it is a customized version of pure Android. Here’s a quick glossary of terms for you to refer to later on if you’re confused:
