I stupidly thought today that I would try out KnightOS and then if I didn't like it I would go back to TI-OS. However, now when I try to load back TI-OS TI-Connnect does not recognize my calculator, therefore I do not know how to reload back onto TI-OS. On KnightOS.org it claims you just have to follow their simple instructions if you want to go back on TI-OS but since TI-Connect won't recognize my calculator I do not know what to do. I currently have this loaded on a TI-84 Plus CSE. Please help! Thanks!

Luckily, the boot code will save you. Hold down the [DEL] button, hit the tiny RESET button on the back of the calculator with a pen tip, and release DEL. The calculator should be in a state where you can re-send the OS with TI-Connect.

I can't thank you enough! Thank You! Thank You! Thank You!!!

Hi,

I figured I would post in here instead of starting a new thread. I did the same thing to my TI84 Plus Silver Edition.

What is the reset sequence for mine? I recently installed KnightOS to try it but now I want the original OS back. Thanks in advance for help.

Same thing, except there isn't a reset button. Press [ON]+[DEL] while reinserting a battery (forcing the CPU to reset). You may need to remove the backup battery too; I'm not certain.

Edit, I'm going to try another method, going to take all the batteries out. Might clear the memory.

The download page has uninstall instructions (for anyone else that gets stuck)

Update,

I tried this sequence. Connect your USB cable, go to settings on KnightOS. Upgrade OS. Then browse for your original TI OS. Select it and it will do it's business.

For future reference, taking all the batteries out won't erase the OS, as it's stored in Flash memory, not RAM.

Yes sir, found out.

I am also trying to get rid of knightos but i dont have a backup os for the TI 84 C silver edition. Please help me guys!

Reviving this thread as I also cannot get rid of KnightOS. I tried the above sequence but I get the following error message:

ERROR!
Press any key to turn unit OFF. Then turn unit back ON.

I've tried this a number of times and still get the same message. When I attempt to hook the calc to the computer and use TI Tools, the tools can't even query the device.

Anyone have any other ideas or is mine just fried?

I have the same problem. Can ANYONE find a fix for this? i really want my calculator back as i need it for school...

On-del for monochrome calcs (83+/84+/se), Del-Reset for colour calcs. The calc wakes in listening mode, right? Also, KnightOS has a setting inside it that should allow you to get the old OS too; look for an update option in KightOS, iirc.

Ill see if I can bother SirCmpn to add an inturruptive pop-up warning before download goes through. But, I mean, there IS a warning right above the download telling you to be careful, and that KOS is feature-incomplete....

I have tried ON-DEL and then restoring tiOS, and using knightOS's built in OS update feature. I know that there is a warning about the download, but i thought they would at least check to make sure the "uninstall" feature works before releasing it as a "stable" release.

I figured it ou! you have to restore to an old version of knightOS and then you are able to restore tiOS from TI-Connect!!!

I'm glad you were able to solve it. I'm biased, having had problems both with the main developer of the OS and with the project itself, but I do feel that there isn't sufficient warning that it will be hard to uninstall the OS once installed (and that it doesn't still allow you to use the TI-OSes math features, which is obvious to us programmers but not as obvious to the layperson).

@KermMartian:

http://www.knightos.org/download/ big warning at the top, also instructions on how to re-install TI-OS. You're welcome to make a PR if you think more can be done

And silicongraphics, feel free to submit a bug report with your calculator and KnightOS version.

Excellent, that's good to know! I suspect that KnightOS may be mirrored on other sites without that warning, which could be the particular issue (also my experience is that the average user doesn't bother reading instructions, documentation, warnings, READMEs, etc). Silicongraphics, where did you download your version?