Ti-Nspire CX CAS

Hello,
I was wondering if anyone knew how to downgrade the OS on a Ti-Nspire CX CAS, It was running v2.something when i got it and i tried to upgrade it to v3.1 and fell for a lie made by the Ti-Nspire website
... It was actually v3.5... I read somewhere that if the last letter of the serial code is lower than I that it is down gradable... The last 5 digits of my Serial Number are "0911D"
Any help in any way is appreciated.
Thanks
~Special
PS. I know about the new version of NDless but it seems to crash every 5 minutes when I have it installed
I was wondering if anyone knew how to downgrade the OS on a Ti-Nspire CX CAS, It was running v2.something when i got it and i tried to upgrade it to v3.1 and fell for a lie made by the Ti-Nspire website

Any help in any way is appreciated.

Thanks
~Special
PS. I know about the new version of NDless but it seems to crash every 5 minutes when I have it installed
