Omnimaga

Calculator Community => Other Calculators => Topic started by: Pew446 on October 02, 2013, 01:03:00 am

Title: Looking to help out with downgrading J Model TI-nspire CX calculators.
Post by: Pew446 on October 02, 2013, 01:03:00 am

Hi all. I just recently bought a brand new TI-nspire CX calculator without doing any research ahead of time, and unfortunately I have the J Model calc. (P-0413J)

OS Version is 3.2.4.1237
Boot1 is 3.0.0.99
Boot2 is 3.2.4.7

I was hoping to play some GBA games on my calc, but from what I've read, there is no known way to downgrade the J models. I don't know too much about hacking calculators, but I do have a logic analyzer and am willing to do some tests if it's needed. I am using the Saleae Logic, (8 bit) so if you guys ever need something recorded or somethin like that, just lemme know :) I'm willing to help in any way I can to be able to play some GBA games. ;P

Title: Re: Looking to help out with downgrading J Model TI-nspire CX calculators.
Post by: Lionel Debroux on October 02, 2013, 01:38:10 am

Hello,

Thanks for your offer :)
While a logic analyzer could be useful for hardware documentation of the dock connector (and on older models, the J04 connector), the possibility of tampering with the calculator through the connectors isn't very high, and anyway, the fact that using the connectors requires extra hardware makes such tampering impractical among users...

Software exploits are more practical. For those, you need to find out how to decompress+decrypt the boot2 or decrypt the OS (although the tool is available publicly, the decryption keys are not; you can also have nspire_emu dump them for you, provided you can find a copy of CX boot1 3.0.99 somehow), and disassemble the code.