A system on chip includes a random access memory, a read-only memory, and a processor. The processor is configured to, during a development phase of the system on chip, read program code from the random access memory and execute the program code. The program code is developed during the development phase until a completed version of the program code is reached. The processor is configured to, during an operational phase of the system on chip, (i) read the completed version from the read-only memory, (ii) execute the completed version, and (iii) cache data in the random access memory. The processor is configured to, during the operational phase and in response to an improvement to the completed version of the program code being developed, (i) read program code corresponding to the improvement from the random access memory, and (ii) read remaining portions of the completed version from the read-only memory.