Downgrade my Ti

[Manu-maker]

Hi, I have just bought a ti-nspire cx II T and I updated it to 5.4.0257 but to install ndless I need 5.3.0. How can I downgrade it? I have already tried to delete de OS and reinstall 5.3.0.564 but it said that i can't install a older version of OS even if there wasn't OS.

[adriweb]

No

[bahillybeans]

Are there any outside programs that can talk to a cx ii?

[ExpertPhisherman]

Are there any outside programs that can talk to a cx ii?

https://lights0123.com/n-link/ Also, join the Discord if you're going to ask already answered questions: https://discord.gg/P6EFvh96bd

[DenisDziganchuk]

The most likely explanation is that the latest version downloaded is stored in a chip that the calculator has access to through memory-mapped functions or directly. If the version is stored in memory, we can find and override it, using methods that I will not share since this is from private Ndless development. There might also be a way of finding the chip on the motherboard and reading it, although this might be risky, and we aren't sure if there is a chip like that. It might also be in physical NAND memory which we have access to through Ndless.

[Vogtinator]

You don't have to hyphothesize, how that works is well known and documented: https://hackspire.org/index.php?title=NAND_Memory_Layout#Bootdata_Format

[DenisDziganchuk]

So it's just stored in NAND? This means that if we can get C to run using the Ndless compiler, we can write to the NAND, but since we don't have any new exploit, this is the same as getting Ndless to run.

[DinoRexHub]

Edit it from the computer and send it back some how

[adriweb]

Edit it from the computer and send it back some how

That's what installing a new OS would be. Which in our case is not feasible, because they're using a cryptographic signature, so only TI can provide OS images etc.

[elmerthecat]

Sorry, I have not made much progress lately I have a large project in school this month so will likely not make much more progress until december. The most recent thing I have done with it is replace the OS and certifactes entirely only editing the os version info from the manifest.txt file. The software still accepts (or thinks) thats its the newest version but stops and says the file is corrupt. This makes sense as when I open it is 7-zip some of the files are missing and the other ones show that they have been edited (although I think I have figured out the crc records) and like LambdaLaboratories said distruibution TI software (without permition and we all though thats not happening) is illegal so if you want more "Information" I will post it on the chat room on my website https://www.thecalculatorguy.net (It does not liik the best but I can promise the security is pretty good (it has had some "real world" testing but thats another story) anyway im rambling, but I will post some things on there (room name: ndless) showing what I have done so maby some other poeple could look at what I have done and contruibute to this.

By the way I am TheCalculatorGuy ;)

Any updates on this?

[DinoRexHub]

ohmygod ti is so stupid we bought the calcs with our own money it is our right to change them the way we want

[elmerthecat]

ohmygod ti is so stupid we bought the calcs with our own money it is our right to change them the way we want

Fr. I feel like the golden age of calc modding was ti-84 era. Barely any projects care coming out anymore, and I wish that more people would join and contribute to the calculator community.

[DinoRexHub]

ye most projects I see for the nspire on omnimaga and ti planet are all from 2014 or sum

[elmerthecat]

ye most projects I see for the nspire on omnimaga and ti planet are all from 2014 or sum

Not just the nSpire, basically all calcs are like that except for a few minor projects. I hope to learn C someday, then maybe I can start porting some stuff to the nSpire, but for now, we just have to rely on others.

[DinoRexHub]

I would say if u know python then u can use lua to program and therefore luna.

[elmerthecat]

I would say if u know python then u can use lua to program and therefore luna.

Some of the issues with that (as far as I know, I dont know any programming languages atm so correct me if im wrong) are that a. Python and Lua are slower than C (especially python, making it almost unusable for most games), and that B lua programs are a bit more limited in what you can do than programs running C or Arm, I.e no holding down buttons in lua programs. I could be wrong on either of these reasons tho, so if someone knows more than me, please correct me or add more. (;

[DinoRexHub]

o ye btw apparently on aops, the ndless FAQ talks about if u corrupt ur calc u can delete the os and that's got me thinking that what if u corrupted the calc so badly that it's os downgrade protection fails. could u downgrade the os to an ndless supported version? or what about flashing the bootloader like in nLoader?

[elmerthecat]

o ye btw apparently on aops, the ndless FAQ talks about if u corrupt ur calc u can delete the os and that's got me thinking that what if u corrupted the calc so badly that it's os downgrade protection fails. could u downgrade the os to an ndless supported version? or what about flashing the bootloader like in nLoader?

I think that the risk is, that assuming that you were to corrupt it by simply unplugging it during an upgrade, what if we are wrong and the first thing the calc does is write the downgrade protection. Then, if this does not work, you will be forced to upgrade to a higher os. Just my theory tho.

[DinoRexHub]

I've been scouring the internet but haven't found anything related to another jailbreak for nspire/cx/cx II apart from ndless. have you found anything?

[elmerthecat]

I've been scouring the internet but haven't found anything related to another jailbreak for nspire/cx/cx II apart from ndless. have you found anything?

Not today but every once in a while I’ll take like a half hour to an hour to find something. A few people on Reddit or GitHub sometimes say that they are trying to do it themselves, and then just go silent.

[DinoRexHub]

If i can find a way for my computer to recognize the nspire as some sort of unprotected storage device when I plug it in, I might have a fighting chance at editing the nspire files and deleting downgrade protection. any thoughts on that?

[adriweb]

No, that's not possible and isn't how the downgrade protection is done. Just stop.

[elmerthecat]

If i can find a way for my computer to recognize the nspire as some sort of unprotected storage device when I plug it in, I might have a fighting chance at editing the nspire files and deleting downgrade protection. any thoughts on that?

Im pretty sure the files are all signed so you cant edit the code.

[DinoRexHub]

on an unrelated note, does the nspire have some sort of internal bios?

[elmerthecat]

on an unrelated note, does the nspire have some sort of internal bios?

Doesn’t everything have a bios?

[adriweb]

There are several steps to boot the OS, one verifies the next.

1. Boot ROM (this is flashed once in factory, can't be updated)
2. Boot Loader
3. OS Loader
4. OS

And there are even more partitions.

[DinoRexHub]

Okay nevermind.

Have you guys heard of TNOC? I haven't read much but according to the description: "TNOC is a tool which lets you remove the boot2 and samples from a TNO/TNC file."

Not completely sure, however it seems as though boot2 is part of the boot loader (it's literally in the name) and if we can remove part of the boot, that's progress, right?

Idk though because TI might have patched it.

O ye here's the download link: TNOC DOWNLOAD

[elmerthecat]

Okay nevermind.

Have you guys heard of TNOC? I haven't read much but according to the description: "TNOC is a tool which lets you remove the boot2 and samples from a TNO/TNC file."

Not completely sure, however it seems as though boot2 is part of the boot loader (it's literally in the name) and if we can remove part of the boot, that's progress, right?

Idk though because TI might have patched it.

O ye here's the download link: TNOC DOWNLOAD

Part of me doubts that they used the same code for the old, monocolor ti-nspire as they did for the new, more powerful cx series.

[DinoRexHub]

Yeah ur prob. right

[DinoRexHub]

o ye btw apparently on aops, the ndless FAQ talks about if u corrupt ur calc u can delete the os and that's got me thinking that what if u corrupted the calc so badly that it's os downgrade protection fails. could u downgrade the os to an ndless supported version? or what about flashing the bootloader like in nLoader?

I think that the risk is, that assuming that you were to corrupt it by simply unplugging it during an upgrade, what if we are wrong and the first thing the calc does is write the downgrade protection. Then, if this does not work, you will be forced to upgrade to a higher os. Just my theory tho.

rn i'm genuinely considering updating my nspire then unplugging it to corrupt it.

[Carlos4621]

o ye btw apparently on aops, the ndless FAQ talks about if u corrupt ur calc u can delete the os and that's got me thinking that what if u corrupted the calc so badly that it's os downgrade protection fails. could u downgrade the os to an ndless supported version? or what about flashing the bootloader like in nLoader?

I think that the risk is, that assuming that you were to corrupt it by simply unplugging it during an upgrade, what if we are wrong and the first thing the calc does is write the downgrade protection. Then, if this does not work, you will be forced to upgrade to a higher os. Just my theory tho.

rn i'm genuinely considering updating my nspire then unplugging it to corrupt it.

I've already tried, I didn't get anything

[Thinkpad-x230-user]

I think I've put a modified os onto my ti nspire. In notepad i changed this line: ÞŒfX›cX›c 
€JTI-Nspire €1C€á
€. 6.20.333€. 6.20.333€ˆ & ‚. 1.4.0 PK to ÞŒfX›cX›c 
€JTI-Nspire €1C€á
€. 5.3.0.564€. 5.3.0.564€ˆ & ‚. 1.4.0 PK I was able to put this onto my calculator, I used os 6.2.0 because I accidentally upgraded. I wonder what this did.

EDIT: I did not get the os set up screen when I installed the modified os, so I think that it didn't work

[Thinkpad-x230-user]

I wasn't able to downgrade with the modification to the os. I was hoping that it would put the older os into the minimum os rom in the calculator.

[dillon42gamer]

Any updates on this? I recently purchased a ti-nspre cx ii as an upgrade from my ti 84 ce as i though i would be able to play more games and more programs with more powerful ram and storage but am exteremewly dissapointed on how the nspire community has been falling off.

[Thinkpad-x230-user]

No updates unfortunately, I have school to attend and I need my calculator.

[firelane98]

EDIT: (USELESS) I found this in TI-Planet, it's realtively unused and was made a while back, its also for the original TI nspire, it just says that it didnt need ndless, so I wonder if this can be made for the CX II Link: https://tiplanet.org/forum/archives_voir.php?id=3584

[adriweb]

No that was only for the very old calcs before CX

[Thinkpad-x230-user]

I think I might of did it?

[Thinkpad-x230-user]

My nspire thinks that the OS is corrupted. To fix it, somebody needs to rehash the os replacing 5.3.0 with 6.2.333

[Vogtinator]

You cannot downgrade the OS that way.

[Thinkpad-x230-user]

the .tcc2 is just a .zip file. Maybe I can edit the boot.img?

[adriweb]

No. This has been talked about many times before, please read earlier #300 comments. It's not possible, stop wasting your time (and other people's).

[ExpertPhisherman]

It’s cryptographically signed. You can’t “edit” the update file.

[Thinkpad-x230-user]

Why isn't there something like downgradefix for the CX?

[jogh3]

Has anyone tried deleting enough of the OS/Boot loader so that it has reference point for older or newer OS and will just let you install what ever OS you want?