Not an issue perse but can anyone (such as fabian) send me info qbout how we access files that are not shown in the software?

[Vogtinator]

Which files are you referring to in particular?

[SomeoneOrderedATransfem]

Hi Fabian, I was mostly referring to how we would access files on the TI-NSpire that may not show up in the desktop software. So basically, Is there a method to access the calculator like a hard drive? Please do note that I am not able to install endless so I am trying to find a method to downgrade.

On Sun, Feb 26, 2023 at 11:22 PM Fabian Vogt @.***> wrote:

Which files are you referring to in particular?

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[Vogtinator]

You mean files outside of /documents/? Without ndless that's not possible.

[SomeoneOrderedATransfem]

Ah. do we know how TI has made its software to interact with the calculator? if we know that then we may be able to develop an app that can interact with items outside of /documents/

On Mon, Feb 27, 2023 at 7:43 AM Fabian Vogt @.***> wrote:

You mean files outside of /documents/? Without ndless that's not possible.

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[Vogtinator]

That uses the NavNet protocol, which can only access /documents/.

[SomeoneOrderedATransfem]

are there other protocols we can use? such as maybe hijacking the protocol that TI uses to install the OS? I'm not entirely sure how OS downloads work but I don't see anything in the calculator files that suggest that the OS is installed inside /documents/. I also don't know where the file that stores the current OS version is stored, but if it is inside /documents/ then we could delete the OS and the OS version that is saved after deleting the OS.

[Vogtinator]

Pre CX II, the OS was just a file in the filesystem. On CX II, it has its own partition in the flash.

The downgrade protection is part of the "bootdata" partition in the flash, not on the filesystem. Otherwise you could just format the filesystem from boot2/bootloader to reset it.

[SomeoneOrderedATransfem]

The downgrade protection has to be updated when the OS is updated. we could use that and maybe hijack the OS install. Maybe we take apart the code of the student software to access the boot data upon updating the OS?

[adriweb]

It's the calculator that updates the field not the computer... TI may not be the best at security but they're not that bad lol

[SomeoneOrderedATransfem]

So, basically, we have to hack the calculator process which updates the version, which also most likely has a legality check inside the calculator. Also keep in mind that I have never worked with the TI calcs in a coding sense.