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.

Customs clearance at destination is usually handled by a licensed customs broker, not the exporter. You can hire one yourself or use a broker recommended by your shipping agent. The typical flow: your broker files the import declaration using the documents the exporter must provide — the commercial invoice, packing list, bill of lading, and the certificate of origin. Depending on your country's rules, you will also need to pay import duty, VAT or sales tax, and any excise or environmental levies before the car is released. Things that commonly delay clearance: mismatched VIN numbers between documents, missing pre-shipment inspection certificates (required in some African and Middle Eastern countries), or non-compliance with your country's used-car import age limits. Budget 3–10 working days for clearance after the vessel arrives, plus storage fees if documents are incomplete. Tip: send all documents to your broker for review before the ship departs China — fixing errors at origin is much cheaper than demurrage at destination.

We will use a megohmmeter (insulation resistance tester) to measure the insulation resistance of the high-voltage bus. If the resistance value is below the national safety standard, it indicates a risk of leakage, and the vehicle will be deemed unqualified.