Summer 2009, the TI community factored all 512-bits RSA keys used to validate OS and Apps installation on TI-z80 and TI-68k Flash calculators.
This opened the way to:
- patched OSes and Apps
- 3rd party OSes and Apps
Some of the patches disabled the TI-84 PTT mode, and TI must have been bothered with that.
Spring 2011 (http://ourl.ca/11565), we discovered a new 1.03 Boot Code on the new TI-84 Pocket and on TI-84 Plus hardware revision Q and above.
That new Boot Code adds a 2nd validation check for the OS installation with a 2048-bits RSA key only included in OS 2.55MP.
So you had to:
- wait 6 additional minutes at the "Validating..." screen after sending an OS
- stay with the lastest 2.55MP OS which breaks compatibility with several asm games
(http://i.imgur.com/9cowL.jpg) (http://i.imgur.com/aO10u.jpg)
Then, Brandon Wilson discovered a way to reflash the TI-84 Boot Code. You could then downgrade your Boot Code to 1.02 or 1.00 and then downgrade the OS. ;D(http://www.omnimaga.org/Themes/default/images/gpbp_arrow_up.gif)
But you had to get such Boot Code image, which is different between basic and Silver Edition TI-84.
(http://i.imgur.com/MFjW8.gif)
Brandon then released EpicFail, a Boot Code 1.03 patch. No need to dump the Boot Code on a model you don't own anymore.
But you might break your TI-84 permanently if anything bad happends during the Boot Code flashing, and using such tools might void your warranty from TI point of view.
Brandon then worked on a 3rd way: a patched TI-84 2.43 OS which can be installed on Boot Code 1.03 because of some exploits. But it could not be shared publicly because of copyright reasons...
On TI-Planet we just converted that into a dynamic patch for every TI-84 OS; Make103! ;D(http://www.omnimaga.org/Themes/default/images/gpbp_arrow_up.gif)
You can now make every TI-84 0.46 to 2.53MP OS installable on your original Boot Code 1.03! ;D(http://www.omnimaga.org/Themes/default/images/gpbp_arrow_up.gif)
It also works with TI-83 Plus OSes patched to be installed on the TI-84.
For now it doesn't work with 3rd-party OSes which are much smaller and don't reach the 2048-bits RSA key location (and so exploit) in ROM.
Download from the TI-Planet news:
http://tiplanet.org/forum/viewtopic.php?t=9333