It depends. Cryptographic hashes were designed to prevent these so-called "collision attacks."
MD5, however, is compromised. It depends on what hashing method TI is using.
It'll be awesome if it turns out to be this easy

MD5 is not completely down and out. Besides, I would presume that the nspire might use SHA-1.  Just a theory considering the 1024 bit key.

And Because of the way hashes work, It would be easier to factor the RSA keys then trying to find a match.

any news about this?

That's one fishy necro! :O How did you happen to stumble onto this again anyways?

Very interesting
Got to research some more details.

You can do that now already.
But the thing here is to have an alternative OS working without Ndless, and installed the the flash.
This would give also much more power to the user.

jimbauwens pointed me to this topic.

Is there any way to know which method they (TI) used?

The method was publicly documented on Hackspire months before this thread was started
Namely, TI uses SHA256, which is much stronger than SHA-0 or SHA-1, and of course even more stronger than MD5 (used in TI-Z80 and TI-68k series).

Finding a useful cryptographic hash collision would be like winning 10-15 times at the lottery, instead of 20-30 (or 40-60) with TF on the public RSA keys... that's immensely better, but still completely hopeless. Neither method is a usable way to achieve our basic user right, our freedom to tinker with the hardware we own.