Have a look at the "Supervisory Memory" and its APIs in t5he "System Reference Guide" (Creator Help)
In addition to the Flash memory PSoC4 BLE devices also have a small amount of Supervisory Flash (SFlash) which is not overwritten during a typical programming cycle and can be used to store manufacturer-specific data.
In Creator go to File-> Code examples and select SFlash_Example for PSoC4200BLE. This example should be helpful to you.
Vasanth R S