Micro-USB or proprietary cable with data transfer capabilities (avoid charge-only cables).
What (if any) are you seeing when you dial *#06# ? coolsand rda imei repair tool
When corruption occurs, the device displays "Invalid IMEI," "Null IMEI," or "0000000000000," blocking registration on any carrier network. Top Coolsand RDA IMEI Repair Tools the device displays "Invalid IMEI