LineageOS on old android phone

phone model LG Optimus L90 

installing Lineage OS

full instructions: https://lineageosroms.com/w7/#rooting-your-device

on phone:

go to Settings > About Phone > Software options, click on Build Number 4-5 times until Developer options are enabled

on linux desktop:

download Platform Tools https://dl.google.com/android/repository/platform-tools-latest-linux.zip

extract the zip 

plugin in phone via USB cable to desktop, try MTP mode

on desktop go to platform tools folder and run
> ./adb devices

if devices dont show, try PTP tether mode via usb cable

mreider@mrxmini platform-tools ./adb devices                                                                                                                                                                                   130 ↵

List of devices attached

LGD4154e16c0e8 device

on desktop install necessary build tools

mkdir ~/Downloads/roms

mkdir ~/Downloads/roms/bin
mkdir ~/Downloads/roms/lineage

cd ~/Downloads/roms/bin
curl https://storage.googleapis.com/git-repo-downloads/repo > ~/Downloads/roms/bin/repo

chmod +x bin/repo

cd lineage
repo init -u https://github.com/LineageOS/android.git -b cm-14.1

source build/envsetup.sh

breakfast w7