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 will remove the chassis guard to physically inspect the battery pack's lower shell for serious dents or scratches, and check for signs of mud or sand intrusion in the waterproof vent at the edge of the battery pack.

Remote mechanical assessment relies on documented evidence: 1. Cold-start video: Ask for a video of the engine starting from cold — listen for rattles, watch for smoke (blue = oil burning, white = possible head gasket issue). 2. OBD scan: A full diagnostic scan reveals fault codes in the engine, gearbox, and electronics. Request the raw scan report, not a screenshot summary. 3. Service records: Cross-check mileage against maintenance records and inspection stickers; consistent records indicate a cared-for car. 4. Fluid check: Photos of the oil dipstick and coolant color tell a lot — milky oil or rusty coolant are red flags. 5. Test drive video: A short drive video shows gear shifts, braking, and steering behavior. Combine these with the pre-shipment inspection report. A seller who refuses to provide cold-start video or OBD data is a warning sign.