1. Nandroid backup
2. Never ever format internal and external card
3. You can play around without worrying any data lost as long as you don't do point 2
Here I'd shortcut , using titanium backup or something similar to backup your apps and contacts and something you concern to be important
Install new ROM, of course remember wipe, and then use titanium backup to restore the apps and data , there you go, with new system
来自我的 GT-I9505 上的 Tapatalk