I recently bought a ti nspire cx and I jail broken it with endless on os version 4.0.3 with the last letter on the back of the calculator being "V" with a boot 2 code of 4.0.3.49. 
Is there any possible way for me to downgrade to a firmware that is lower than what I bought it on?
Is there a downgrade fix compatible with OS v 4.0.3?
I know that I can remove some root files (or data in them) to be able to make it so that I can downgrade but my friend bricked his calculator trying that so I don't want that.