If you've read about hacking or rooting your Android phone (or tablet, or media player) you've seen the word Nandroid used. When tinkering with your device, there's always a very good chance you'll be left with firmware that won't boot, leaving you in a bit of a lurch. A Nandroid backup can mean the all the difference here.
What it is, is a full backup of partitions on your device's NAND flash (NAND stands for NOT AND, a type of electronic logic gate -- it's like the hard drive of your Android device) storage. Think of it as a snapshot of the current running system, and it can be used to restore that that point at any time. Both user data and system files are backed up, and it's a far cry from what we think of when talking about a traditional backup from other software. In fact, it's something that many folks wish was part of the stock Android recovery. Yes, to preform a Nandroid backup you'll need a custom recovery on your device so that the executable files and scripts are there. These have been left out of the stock recovery, likely over issues that would arise if users can backup proprietary files.
Getting the custom recovery on your device is the hardest part, thankfully. Once installed backing up and restoring with Nandroid is simple, involving nothing more than choosing the option and verifying -- no wires needed. Even if you never plan to hack your phone ( I like stock ICS on my Galaxy Nexus), flashing a custom recovery and running a Nandroid backup is always a good idea. You can find more information about custom recoveries, as well as methods to install and use them, in the device-specific section for your device in the Android Central forums. Give it a look, and decide if it's something you're interested in doing.
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