The Kindle Fire HD 7 is a pretty solid device that uses a forked version of Android 4.2.2 "FireOS". This device has had a full fledged Android build ported over to it. There are plenty of other mods that have been released for this device as well. One of the latest developments is a new kernel by kernel dev "SafinWasi" which allows you to charge your Kindle Fire HD 7 super fast. The mod enables you to charge your device with the full power of your AC or USB charger. This means that your device will be charged much faster than if you used the standard throttled current. You will need to boot the Kindle Fire HD 7 into fastboot mode, before flashing the kernel and rebooting the device. Once complete you can activate and deactivate the mod with an adb command, or you can opt to use the developers app which will only set you back $1.49 and is much more convenient. Head to the source link below for the download.
Via XDA