A quarterly bundle of newly fixed security vulnerabilities across the Android codebase. Distributed as a list of patches and security branch updates for older but still supported Android versions, with the current version tagged quarterly.
Bootloader
A general term for a link in the boot-chain that is run each cold-boot which loads the kernel, OS, and related components.
Bootloop
A state in which the device never reaches the end of it’s boot phase and continually starts over
Useless when used in describing an error, since there are many points in time during a device boot where it might abort and start over, e.g.
At the vendor splash logo
At the LineageOS bootanimation (three white circles rotating on the screen)
Reaching the lock screen or setup screen but immediately restarting
etc.
Bricked
A device which cannot be recovered from a fatal failure by any means, leaving it in an unoperable state which is not recoverable by any means outside of OEM repair.
People often use this word in places where they just mean a Bootloop and their issue can be fixed using either button presses or readily available software tools
Custom ROM
A (self-)built Android version with changes on top of the AOSP (Android Open Source Project)
Data
Data is everything added by a user - installed apps and their data, settings, and media (pictures, videos, audio files, etc.)…
If the installation or upgrade for your device calls for a Factory reset or unlocking the bootloader, this is the data that will be deleted
Degoogled
A term describing that an OS has no software parts from, or that attempt to connect to Google
LineageOS is not explicitly degoogled, we simply don’t ship GApps due to licensing
Factory reset
Despite the name containing “factory”, performing such a reset is returning the device into a state “without user modifications”, not back to the Stock ROM
Firmware
Included in the Stock ROM - A layer of software required to allow the OS to interface with the hardware
Not the same as a Custom ROM or ROM in general but sometimes included in Custom ROM installation packages/instructions
GApps
Google Apps, usually consisting of GMS (Google Mobile Services), the Play Store, and a varying amount of the native Apps made by Google (Dialer, Messenger, Calender, etc.)
Google Apps are not preinstalled on LineageOS but can be installed during installation of LineageOS, please see your device’s Install guide for more information
OEM
Original Equipment Manufacturer, the one who sells and manages software on a given device (e.g. Samsung, Motorola, Google)
QPR (Quarterly Platform Release)
Mid-cycle updates to a given Android version, landing every few months. QPRs bring not just security fixes but also bug fixes, performance improvements, and feature changes.
Root
People sometimes wrongfully use this when they mean Unlocking
Refers to being able to access and modify the contents of read-only partitions via apps or a shell (usually involving a “superuser” (su) binary)
Some apps “detect” root access on LineageOS (which does not come rooted!) when they actually mean “modified device”
LineageOS does not offer any rooting solution (despite adb root) and does not provide support to install any
Stock ROM
The variant of Android the vendor/OEM shipped on the device from the factory, this applies to OTA (over-the-air) updates issued by the OEM
Unlocked
There are two types of unlocking when discussing smartphones:
Carrier unlocking: You can use the device with SIM cards of any carrier
Bootloader unlocking: You can run unsigned operating systems/kernels. This is the type of unlock you need to install a Custom ROM
Some carriers allow for (or are obliged to do so by law) removing the SIM lock but still won’t allow unlocking the bootloader