The things to do before upgrading an Android phone, or changing the firmware on your Android phone:

  • Enable ADB debugging
  • Turn on USB and mobile network
  • Change all unlock settings, including fingerprint, password, PIN to none
  • Move private files to public.
  • Backup the existing partitions
  • Backup /data/media (certain recoveries, TWRP, do not backup /data/media, so make a copy.)

The backup needs to be the last step.  

Why would I need to do this?

This is because if there's an issue with the upgrade or the firmware,

 

  • I can use adb to get into the phone, and fix it. In order to get into the phone, adb needs to be enabled on the phone, and the private turned public files are accessible.
  • I can access the files before they get encrypted and lost without any possibility of getting recovered.