The keyword "best" implies efficiency, permanence, and safety. For Coolsand RDA chips, there is no universal "secret code" like *#06# to repair the IMEI (that only displays it). Instead, the best methods involve one of three approaches:
This method is the "best" because it addresses the root cause: the data in the protected memory partition. A dialer code cannot force a write to a locked boot partition, but a specialized box working in BootROM mode can. coolsand rda imei repair code best