How to Read a Nook Book on a Kindle Fireby Ashley Poland
If you have an extensive library of books purchased through Barnes & Noble, replacing them all with Kindle-friendly versions is prohibitively expensive. You can read your Nook books by installing the Nook Android app on your Kindle Fire. However, the Nook app is not available in Amazon's Appstore (surprise). The easiest solution is to sideload the Nook app onto the Kindle Fire. However, it isn't the only method of reading your Nook books on the Kindle.
Sideloading the Nook App
While the Nook app for Android devices is available from the Google Play Store, the store is not available for the Kindle Fire; the only way to get the Play store is through rooting the device. The simplest way to add the Nook app to the Kindle Fire is to download the Android application package (APK) file and install it manually on your Kindle. This doesn't void your warranty, unlike more drastic measures. To enable sideloading on your Kindle Fire, open the settings and go to "More." Select "Device" and slide the "Allow Installation of Applications" option to "On." You can use your mobile browser to download an APK of the Nook app from websites like GetJar, which is recommended by Sharon Vaknin of CNET. Consider adding an anti-malware program to your Kindle Fire before sideloading apps; several are available from the Android Appstore.
If you want to read your Nook books in the Kindle app, the solution is to download the Nook books, strip the digital right management (DRM) and convert them to the MOBI format that the Kindle app can read. The legality of removing DRM is slippery; while the Digital Millennium Copyright Act allows you to make backups of your own content, removing DRM for your own backups is of questionable legality but obviously benign if you aren't sharing the files and paid for the originals. If you choose to remove the DRM on your files, you can use programs like Epubor or the Apprentice Alf plugins for Calibre. The Calibre program also converts e-books to several formats, including MOBI.
Downloading Your Nook Books
Before you can remove DRM on the e-books you've purchased, the Nook for PC application allows you to download books from your Nook library to your computer. Another solution is to use Calibre to manage your e-books; it can pull the ePub files from your Nook and put them on your computer.
Rooting the Kindle Fire
"Rooting" your Kindle Fire to install the Nook app is extreme. Rooting allows you greater control of the Kindle Fire by removing restrictions on the "root" folder of the system. One of the most notable is the ability to install the Google Play Store on the rooted Kindle Fire, which gives you access to the Nook app from a managed channel, rather than downloading the APK file from a website. Rooting the Kindle Fire voids your warranty, and the root may need to be performed later if an Amazon update voids the rooting. Rooting requires several steps, starting by downloading the Kindle Fire Utility.
This article refers to tools, software and laws as they were in December 2013. Hardware and software availability, features or price may vary with time.