In a memory system including a flash memory and a memory controller having a cache memory and a nonvolatile random access memory (NVRAM), a method of operating the memory system includes; receiving a write request specifying a write operation directed to a page of a designated active write block in the flash memory, storing a page mapping table for the active write block in the cache memory, generating update information for the page mapping table stored in the cache memory as a result of executing the write operation, and storing the update information in the NVRAM, and storing an updated version of the page mapping table in the flash memory after execution of the write operation is complete.