Transfer software to your Kindle Fire: Turn your Kindle Fire on and unlock the screen. Then connect it to your computer using a USB cable (sold separately). Drag and drop the new update file from your computer to the kindleupdates folder on your Kindle drive. (The drive is typically displayed as a "device" icon).
Monitor file transfer and disconnect: Check your file transfer progress to ensure the file transfer to your Kindle Fire is complete before disconnecting. After the file has transferred successfully, tap the "Disconnect" button on your Kindle Fire screen to safely disconnect your Kindle Fire from your computer. Disconnect the USB cable from your Kindle Fire and your computer.
Start the software update: Ensure your battery is fully charged. Tap the Quick Settings icon in the top right corner of your screen, then tap "More..." then Device. Select "Update Your Kindle." (This option will be grayed out if the most recent update has already been installed or if the file transfer was not successful.) Your Kindle Fire will restart twice during the update. After the first restart, you will see the Kindle Fire logo on the screen.
Once the update is complete: The Device screen will display "Current Version: 6.3.1" when the update is complete.
If you cannot successfully update your Kindle Fire software using the instructions above or encounter any difficulty with your software update, please contact Kindle Support by clicking the "Contact Us" button in the right hand column of this page.