How to Manually Update your Nook Color
I. What You Need
1. Download the update to your computer desktop from here.
2. Do not modify the name of the file, or try to open it; it should be a .zip file.
3. Your NOOK must have at least 20% battery remaining in order for the device to update.
II. Moving the Software Update to Your NOOK
1. Connect your NOOK to your computer via the USB Cable that came with it (the cable that you use to charge it).
2. A removable drive should show up in My Computer for Windows, or on the desktop for Mac.
3. Your NOOK should display “USB Mode” on the screen.
4. Drag and drop the update to the removable drive that popped up. Do not move it to any folder, just the main directory, or the update won’t work.
5. Once the file has transferred, eject the NOOK drive safely from your computer.
III. Updating the NOOK
1. Your NOOK will recognize the software automatically, but will not update until it is in sleep mode.
2. Do not shut down your NOOK while it is installing the new software.
3. After the installation is finished your NOOK will automatically reboot.
4. Once the update is complete, and the device has restarted, you should see an “n” on the lower left status bar, which gives you more information about the update when pressed.
5. If you want to make sure you are running the latest version go to Settings -> Device Info -> About Your NOOK and make sure the version number matches the most recent update.
Thanks to Barnes and Noble for the original instructions found here.