Once you're rooted and have a custom recovery installed,
the very first thing you want to do is make a
nandroid backup. Words cannot describe how vital that is. Allow me to explain:
A nandroid backup makes a snapshot image of the phone's entire current state and saves it to a .zip file in user memory/SD card. That way, you KNOW that if something goes awry, you can flash it back to a known good state.
Let's say that you want to flash a new ROM, or just delete some bloatware. You proceed, follow the steps as best you can, reboot the phone, and it boots up and continuously errors out and nothing works. Or worse: the phone does NOTHING. Black screen and nothing else. Or it bootloops and never boots. What can you do?
Go back into recovery, wipe the phone and restore your nandroid, which takes your phone back to that moment in time when it worked. Then you can figure out what went wrong and try again... knowing that if something else fails, you can restore again.
If you didn't have that nandroid backup, what would you do? You'd literally have to somehow get the original factory image flashed onto the phone and start completely over. Good luck taking it to your provider, since rooting voids your warranty. Point is, I can't count the number of posts I've read from desperate new members who deleted things, skipped steps, flashed the wrong file, etc. with NO BACKUP. And they're pretty much stuck with an expensive paperweight.
Sorry for the long-winded diatribe, but I can't emphasize enough the importance of the nandroid backup. Thanks for listening
