Once the car system (especially in a closed ecosystem) undergoes a major version upgrade, its bootloader is usually locked, preventing downgrades. If this happens, there is basically no solution in an overseas environment. Therefore, we strongly warn: do not blindly insert a USB drive to upgrade while offline.

We maintain an absolute skeptical attitude. In addition to regular visual inspections, we focus on checking for sediment accumulation around the sunroof drainage channels and look for water stains under the A-pillar trim and front floor mats. This is the only effective physical evidence to determine if the sunroof drainage holes are blocked, leading to hidden leaks.

We will check if the vehicle identification number (VIN) is within the official recall batch. If there are any outstanding safety recalls (such as replacing Takata airbags), we will require the original owner to assist in sending it to an official 4S shop to complete the free recall work before the vehicle is deregistered.