Root access for Android 5.1 with Magisk 22.1-22100

Install Magisk on phone, copy boot.img

Launch Magisk > Install > Select boot.img

DO NOT TICK AVB 2.0 for Android 5.1

adb pull storage/sdcard0/download/magisk_patched.img /home/user/Downloads

BACKUP YOUR DATA!!!

adb reboot bootloader

fastboot devices -l

0123456789ABCDEF       fastboot

usb:5-1

fastboot getvar unlocked

unlocked: no

Finished. Total time: 0.002s

sudo fastboot oem unlock

Press Volume Up on phone (READ MESSAGE!!!)

Shows ==> Fastboot... No need to do anything.

sudo fastboot devices

[sudo] password for user:

0123456789ABCDEF         fastboot

cd ~/Donwloads

ls

sudo fastboot flash boot magisk_patched.img

Sending 'boot' (16384 KB)                          OKAY [  0.464s]

Writing 'boot'                                     OKAY [  2.210s]

Finished. Total time: 2.689s

sudo fastboot reboot

DO EVERYTHING AT YOUR OWN RISK!