Important note about using ROBOTC with the Cortex Microcontroller

This is an important note about using ROBOTC for Cortex & PIC with the Cortex Microcontroller.

Please note that the only version of ROBOTC for Cortex & PIC approved for use with the Cortex is 2.20.1 BETA.

Using previous versions may permanently damage the Cortex Microcontroller. Just powering on a Cortex that was programmed with a previous version can result in permanent damage to the Cortex unit.

The latest version of ROBOTC for Cortex & PIC is available for download here:

-The VEX Robotics Team

Can you be more specific about the damage that might be caused, and how to prevent it from happening? I mean, how can I replace the code without turning the power on even once?

You can burn out the 2-pin H-bridges, this error has been fixed in newer versions of RobotC.


what will happen to the cortex? like how do you know?

wow thats new, a cortex bricker
now theres gonna be a VEX virus going around!
in seriousness, i hope the other team leader didnt do anything to our new cortex yet…
school didnt even start :frowning:


Search guys, this is old news.

Just update and you’ll be fine. :wink:


  1. Leave the Cortex power switch in the off position
  2. Disconnect the 7.2v battery from the Cortex
  3. remove the Vexnet key from the Cortex
  4. Use the USB-A to USB-A cable to connect the Cortex to a computer,
    and the Cortex lights will come on.
  5. Attempt to download new code.
  • There will likely be a prompt to download new mastercode as well, using the IFI loader utility.

con you do the same thing by overheating the cortex?

No. This sort of thing only happens when the firmware tells the motor controller (within the Cortex) to run forwards and backwards at the same time.*

Once the glitch in the way ROBOTC controlled the speed controllers was fixed, all problems were solved.

-Note, this is just a “layman’s” description of what is happening (for clarification purposes).