ndless 를 깔아보지도 않았고,
벽돌 상태를 경험해보지도 않아서 도움드릴 말씀이 없습니다.

이곳도 보셨는지 모르겠는데, 일단 참고해 보세요.
https://ndlessly.wordpress.com/ndless-troubleshooting/

The calculator freezes on boot up with a black and white screen

This issue is not related to Ndless and may happen on a never-Ndlessed TI-Nspire.

Hold Esc+Menu+Minus (Minus near Plus) while pressing the ‘reset’ button to launch the Diagnostic software. It should confirm there is a problem (GPIO error) and will fix it when a key is pressed.