If you are going to be flashing Roms on the Nexus 6 you will want to always be sure to make a full Nandroid backup prior to installing your Rom or mod. A nandroid backup makes a complete copy of your phone's current state. This means text messages, call logs, apps, and all data will be totally backed up. If something goes wrong when flashing your mod you will always have a safe restore point. This is also a good way to run multiple roms. You can flash a rom and back it up then flash another and back it up. Then you will able to go back and forth between them. You will need to be rooted with TWRP installed. Links for both are included in the video's description above. Be sure to subscribe to our youtube channel to be notified when more guides like this are uploaded.