Firmware update should have teensy download instructions

For finding teensy boards in the Arudino IDE as per https://www.pjrc.com/teensy/td_download.html
Otherwise you can't talk to the board

<img width="990" height="239" alt="Image" src="https://github.com/user-attachments/assets/9aff831c-daff-4f29-a373-bd222b933491" />