4S dealership records are directly connected to the manufacturer's database, making the data hard to tamper with and the most reliable, with original parts guaranteed; third-party repair shops usually are not connected, making their data unverifiable. Therefore, we only consider the connected records from 4S dealerships as valid historical documentation.

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.

SOH (State of Health) measures the battery's remaining capacity as a percentage of its original capacity. Two EVs with the same mileage can have very different SOH depending on charging habits and climate exposure, and since the battery represents 30-50% of a used EV's value, the SOH number is effectively the real price tag. A proper certificate includes current SOH percentage, cell voltage balance, charge cycle counts, battery management system fault codes, and often a projected range estimate. In hot-climate markets like the Gulf, a degraded battery degrades even faster, so a documented SOH above 85-90% is strongly recommended. Exporters who provide verified SOH certificates close deals faster and command better prices, so treat the certificate as a core purchase document, not an extra.