I’ve used this tutorial:
You need to buy 3 things. If you don’t need to change the firmware (it’s rather for more advanced users) - you can skip the Atmel Studio.
I just simply flashed with this hex file:
http://bazaar.launchpad.net/~toykeeper/flashlight-firmware/trunk/view/head:/ToyKeeper/bistro/biscotti/biscotti.hex
Please note that it works for Nanjg 105D. It should work also for 105C (with stars to soldier), but did not try it by myself.