Do you want to turn the color of your corner on an Android tablet?

Many people don’t realize this, but under the hood, the NOOK Color is actually an Android tablet. That’s right, a variation of the Android operating system that powers millions of smartphones and tablets like the Samsung Galaxy Tab. Barnes & Noble developed a custom version of Android 2.1 to power its popular e-reader, and when you think about it, at $249, it’s a real deal when it comes to Android tablets. It may not have the same high-performance processor as the Galaxy Tab, but it does have a high-quality display and the hardware is quite capable, especially when you consider that it costs half as much as full tablets. But in its default state, the NOOK Color is limping along; a great e-reader, but very limited applications.

As Barnes & Noble talks about an upcoming Android 2.2 update for the NOOK Color, including an App Store, some of us are growing impatient. It’s possible to update your NOOK Color to run Honeycomb, the latest and greatest version of Android, one that’s been optimized for tablets instead of smartphones. The good news is that the heavy lifting has already been done and updating a NOOK Color to work on Honeycomb or other versions of Android is relatively easy. Better yet, using the technique outlined below, turning your NOOK Color into a fully functional Android tablet is not only relatively easy, but can be done without voiding your warranty.

External dual boot: No need to root

Rooting an Android device like a NOOK Color means that you are giving yourself root-level access to the operating system; in other words, you get administrative levels of accessibility (the highest level of permissions) including the ability to change items that have been locked and to access low-level system files and directories. You may have heard the term “jailbreaking” used with an iPhone, and rooting your NOOK Color is essentially the same idea. Once you have rooted an Android device, you will have full control of the device.

It goes without saying that having root-level access has its risks. If you don’t know what you’re doing, it’s all too easy to delete an important file or change a setting that disables your device. Manufacturers warn against rooting your devices because it changes intended functionality, can cause support nightmares, and can end in bigger problems. The result can be a “bricked” device that no longer works. Rooting your NOOK Color may void your warranty and is not recommended.

But there is another option that does not require touching the default settings; in fact, nothing is installed on your NOOk Color. You need to be moderately comfortable using your computer’s disk tools, but you don’t need to be a hacker by any means. As long as you can run a disk imaging utility (and enter a few lines into the OSX terminal if you’re a Mac user), you’ll be fine.

The NOOK Color has a MicroSD card slot and installing a bootable virtual image of Honeycomb (or another Android flavor, if preferred) onto a MicroSD card is now a possibility. This path gives you the option to boot your NOOK Color into Honeycomb without touching the default operating system installed on the device and without voiding your warranty. You’ll need a Mac or Windows PC to create the honeycomb boot image and a MicroSD card you want to erase (memory card requires 4GB or more of storage and must be at least a Class 4 card in terms of speed read/write). The steps to create the Honeycomb bootable MicroSD card are as follows:

  1. Mount the memory card on your computer.
  2. Download a copy of a virtual image of your Android flavor of choice. You’ll have to google this time (since many of these images are based on developer preview builds of Android builds, the locations change frequently).
  3. Unzip the disk image.
  4. Write the Android disk image to the SD card.
  5. Unmount the memory card from the computer.
  6. Turn off your NOOK Color.
  7. Insert the MicroSD card into the color NOOK.
  8. Turn on the NOOK Color.

If everything worked fine, your NOOK Color will boot into the Android version you chose, turning it into a fully functional Android tablet. Not bad for 20 minutes of work. All your configuration changes, downloads, and modifications from this point on will take place on that memory card, keeping the NOOK Color’s on-board memories pristine. This is where your MicroSD card selection will impact your experience. Because everything is running off the memory card (rather than internal memory), the read/write speed and capacity of the card will have an impact on performance: Class 4 is the slowest of all and each of 6 or 10 classes should make the experience faster. In the same way,

The best part of the dual boot method is that when you’re ready to go back to your stock NOOK Color, all you have to do is turn off the device, remove the MicroSD card, and turn it back on. Voila, back to NOOK Color.