If you are still holding onto the original Kindle Fire then is some really great news. The talented Hashcode has put together a Kindle Fire Jelly Bean 4.2.1 AOSP ROM. This is built straight from Google and is exactly the same software as the new Nexus 7 tablet. So although the kindle hardware has much lower specs than the Nexus 7, at least you can now run the same great fast software. This can breathe a whole new life into the original Kindle Fire and extends its capabilities.
Obviously you’ll need to be rooted and running a custom recovery like TWRP 2.2.x or Cannibal Open Touch. All things seem to be working except for the swype-style keyboard and the multi-user accounts. Small price to pay for a great new software. I would definitely give this ROM a try as I can attest on my own Nexus 7 that Android 4.2.1 is pretty awesome. Hit up the source link to download the ROM along with the require GAPPS. Good luck and remember to always do a full nandroid backup before flashing any new ROM. Always remember that you do everything at your own risk.
Source: Kindle Fire Jelly Bean ROM" href="http://forum.xda-developers.com/showthread.php?t=2041694" target="_blank">[XDA]