I just got a Kindle Fire HD as gift for Christmas. I somehow prefer it over the Nexus 7 because of the sound and screen quality. But one little problem with the Kindle Fire HD is that unlike Windows, Linux doesnt auto-recognize it.
The solution is quite simple though. To be able to mount and transfer files to your Kindle Fire HD on a Linux OS, you will need GMTP. If you are using a Debian based distro, the command to install GMTP will be:
sudo apt-get install gmtp
If you are using Arch Linux, here is the AUR package for GMTP
After that, just connect your Kindle Fire HD to the computer with the USB cable then launch GMTP. When the GMTP window is up, click the "Connect" button on the left corner to connect to your Kindle Fire HD:
When the tablet is connected, to transfer files to it from your Linux computer, just hit the "Add" button and browse to the files you want to transfer: