The Stock ROM is the official operating system version that comes pre-installed on your device. Unlike custom ROMs, the Stock ROM is optimized specifically for your hardware by Wiko.
Latest stable build; available via FirmwareFile (532 MB). Official Wiko Rainbow 3G Stock Rom For SP-Flashtool
Do NOT select "Format All + Download" unless you have a hardware backup box (like Miracle Box). This erases the NVRAM (IMEI + WiFi/ Bluetooth certs), rendering the phone useless for calls. The Stock ROM is the official operating system