I deleted the OS to try to install version 3.1 and ndless, and it still wouldn't let me downgrade. But when I tried to put 3.2.3 back onto the device, it said that I couldn't install a version of the OS the is older than the currently installed version, which doesn't make sense because there isn't an OS installed and the OS I am trying to install is the newest version there is. Now the calculator just is at a screen that says "Operating system not found. Install OS now." Please help me!

Yeah the boot2 version is 3.24.7

Yeah the boot2 version is 3.24.7

Worst case possible then...

The only way is reflashing the Boot2 to version 3.1, but for that you'll need an USB/TTL interface (often referred as RS232) to connect to the dock/J01 connector.

You can find them on TI-Planet, for instance: http://tiplanet.org/forum/archives_list.php?id=OS+Nspire

And you should edit your previous post instead of double-posting

Therefore, for now at least, you're stuck with 3.2.4 or 3.3...
That is, unless you have / can buy / can borrow a RS232 TTL / USB adapter and you're willing to use it for downgrading your calculator's boot2. The procedure is not complicated, but it requires hardware not provided with the calculator.
Yeah, I know, the situation sucks for users, and it's TI's fault...

wait, I thought that with 3.2.4 or above, even the RS232 TTL/USB adapter method didn't work?

Hello, I would like to downgrade my Nspire CX CAS boot2 version because I accidentally updated it, before I knew that it is impossible to downgrade your OS if you have boot2 version of 3.24.7 I also heard about the TNOC tool just after I updated the boot2.

I would just like to have a more specific information about the downgrading progress,
What does the USB/TTL adapter look like? Where do I get one? I have tried to google about it but so far I have found no solutions.

Please help me out

Edit: My model number is P-0712F so its between A and I.

These things are really really cheap. No shipping cost: http://www.ebay.com/itm/USB-To-RS232-TTL-Auto-Converter-Module-Converter-Adapter-For-Arduino-S9-hv2n-/301019253456?pt=LH_DefaultDomain_2&hash=item4616254ad0

Less than $1
If you only use it once this will do. If you plan to use it more often: go for one that's a little bit more expensive. The build quality of this cheap thing will not be great.

Quote from: DJ Omnimaga on January 15, 2014, 05:48:13 pm

This should be the hardware you need and how it looks like. http://ourl.ca/19570/360687

It costs about $10 on Ebay if you live in France or United States. If you live elsewhere, there is a 0.0001% chance that you have to re-mortgage your house in order to afford the USB/TTL adapter (or the shipping fees).

As for the guide, I think this is what you need http://ourl.ca/20292/371533 .

Of course I have quit Nspire stuff since long ago so I am not very familiar with everything, so I wouldn't be able to help much more myself.

Okay, I ordered now the Arduino uno and the adapter for it ( and it was only like 11 euros total . I'm just thinking the part of attaching the wires to my nspire because the wires look like this: http://www.ebay.com/itm/PL2303HX-USB-To-RS232-TTL-Auto-Converter-Adapter-controller-Module-for-arduino-/400565253775?pt=LH_DefaultDomain_0&hash=item5d438cb68f.

I ordered:

Spoiler For Spoiler:

http://www.ebay.com/itm/PL2303HX-USB-To-RS232-TTL-Auto-Converter-Adapter-controller-Module-for-arduino-/400565253775?pt=LH_DefaultDomain_0&hash=item5d438cb68f

and

http://www.ebay.com/itm/UNO-R3-ATmega328P-ATmega16U2-Compatible-Version-Board-Free-USB-Cable-For-Arduino-/370966395125?pt=LH_DefaultDomain_0&hash=item565f51f8f5

i checked the hyperlink.
whats that  thingy for, and how do u use it?