CN900 mini is also an original device by Tjecu but just named and sold by different company (Tjecu is the OEM of CN900 mini) while ND900 sell by Tjecu company directly.
When updating, you must use their own update tool/software though
You cannot use ND900 update software for updating CN900 mini and vise versa which I could not understand why but it works fine if you use the correct one to update.
Download the update software for CN900 mini from here: http://cn900.net/
From what I heard, ND900 is originally made for China market while CN900 mini is for international market.
Tjecu CN900mini reliable source:
http://www.carkeydeals.com/wholesale/cn900-mini-transponder-key-programmer.html 199USD free shipping