Download KnightOS

Warning! KnightOS isn't done, and you may be underwhelmed. KnightOS has no math or graphing support past a simple 4-operation calculator. Additionally, note that installing KnightOS will erase your RAM and TI-OS Archive. Proceed with caution.

Installing KnightOS

Users should first install TiLP or TI-Connect to facilitate the transfer.

  1. Check your boot code version.
    • On KnightOS, look in your system settings for the boot code version.
    • On TI-OS, press MODE, then Alpha+S to enter a self test, which displays your boot code version.
    • Note: TI-84+ Color Silver Edition users can skip this check.
  2. For users with boot code 1.02 or older, proceed normally. Otherwise, read below for additional instructions.
  3. Remove a battery from your calculator, then plug it into your computer.
    • TI-84+ CSE users, press the "reset" button instead of removing a battery
    • SilverLink users on Linux, see below
  4. Hold down DEL, then replace the battery you removed. Release DEL.
  5. Send the OS upgrade
    • For TI-Connect users, use the TI OS Downloader tool.
    • For TiLP users...
      • Windows, Mac: Use the TiLP GUI to send the OS
      • Linux: Run tilp -n <path/to/KnightOS.8xu> as root
  6. Wait for it to complete, remove the cable and press ON, welcome to KnightOS!

Troublesome Boot Codes

Texas Instruments has put measures in place to prevent users from upgrading the operating system on their calculators, starting with boot code 1.03. Unfortunately, this means it will be a bit more difficult for you to install KnightOS. It is possible, so do not fear. Here are your options.

  1. Patch your boot code. It is possible for calculators manufactured before a certain date to patch their boot code to remove the extra validation. This can be more dangerous than the alternatives, but is a more permanent solution. We suggest using Unsigned to patch your boot code. After doing so, follow the installation steps normally.
  2. Use UOSRECV. Brandon Wilson has made a tool available that will allow you to install an unsigned OS on your device. You can get it here. Follow the installation process normally, but instead of removing a battery in step 3, run Asm(prgmUOSRECV on your calculator. Skip step 4.

TI-84+ Color Silver Edition users do not need to follow these steps unless they have trouble without, thanks to another exploit from BrandonW that allows us to circumvent the validation without a complex procedure. A similar exploit is in development for other affected calculators.

Linux and SilverLink

Linux users, please ensure that you are running the latest version of TiLP (you may have to compile it yourself). Recent updates have improved SilverLink support, but it may be buggy. Good luck.

Installing TI-OS

If you wish to reinstall TI-OS, download it from TI. Follow the same instructions for installing KnightOS, but don't worry about your boot code version.

Source Code

The source code is available on Github.
KnightOS is licensed under the MIT license.