I believe you're referring to the TomTom Vio (or similar TomTom devices like the Go, One, or Rider) and the concept of "hacking" it—either for unlocking navigation features, installing custom software, or repurposing the hardware (e.g., running Linux, custom apps, or accessing the filesystem).
: Similar to other TomTom units that have been gutted and retrofitted into vehicle sun visors, some hobbyists explore using the Vio's unique circular housing for custom DIY projects, such as integrating different displays or microcontrollers. Forcing Connectivity Tomtom Vio Hack
While hacking a TomTom Vio can be beneficial, it's essential to be aware of the potential risks and take necessary precautions: I believe you're referring to the TomTom Vio
Risks and Precautions