Hi.  I am trying to downgrade the OS on my TI Nspire.  I have a copy of OS 1.1 on my computer and I want to send it.  I used the method on hackspire.com.  I tried sending the new OS and pulling the keypad when it was installing (I pulled it when it was at 60%).  I then put the 84 keypad back in, turned on, then put the Nspire keypad back in.  The OS 2.0.0.1188 was still there.  How do I downgrade.  Also, what would happen if I changed the file extension of the OS from .tnc to .tno.  Would I be able to run the CAS on a regular Nspire?  Thanks!

If it's an old one (most likely light gray and white or light blue), normally you should be able to completly erase the calc OS by removing a battery, then hold down Home, P, Enter and ON keys at the same time until you get a menu after the loading bar reached half. The following will cause all your programs, games and files to be lost! Then select an option to format the calculator including erasing the entire OS. Once done you need to reboot again then when asked, send a new OS.

If it's a newer Nspire, the one with a touchpad instead of clickpad, you cannot downgrade lower than OS 2.0.

Yeah, this is why I am wondering why he can't downgrade I wonder what could be causing it...

I think I heard about this happenign before too...

That's strange... Are you sure that you have enough free memory on the calc?
Besides, I wouldn't really bother with downgrading right now since Ndless2 will hopefuly be released soon.

Or use calc84's utility.

true, especially if you forget to select it before the calc turns off, and you forgot your cursor position. Good luck trial and erroring