A flash file for the RM-970 is essentially a complete firmware package—a snapshot of the phone’s internal brain. It contains everything: the core operating system, drivers, user interface strings, camera firmware, Bluetooth stack, and even the dreaded operator bloatware. Nokia distributed these files as .exe or .mcusw packages, intended for service centers armed with special flashing boxes (like the famous JAF or Phoenix Service Software).
A popular choice for its "Dead Mode" flashing capability.
Often used with an emulator for older S30 and S40 devices.