You need to know your specific model number. For the Nokia C30, it is usually:

Official stock firmware can sometimes be found on specialized databases like HardReset.info

While OTA updates usually keep your data, manual flashing often wipes everything. Always back up your data before attempting a manual firmware download. Authentication:

He knew the problem wasn’t the hardware. The Unisoc SC9863A chipset inside was still good. What he needed was the original flash file —the complete, low-level operating system image that Nokia’s Chinese manufacturing partner, HMD Global, used to program the phones before shipping. Unlike an OTA update (which patches existing software), a full firmware flash rewrites everything, brick and mortar.