1. A method of operating a memory system which includes a plurality of memory cells and on which are executed a sequence of operations and sub-operations under the control of a state machine, the memory system having a standard mode of operation in which a user can program, erase, and read a memory cell and a non-standard mode of operation, wherein access to the non-standard mode of operation occurs upon detection of a non-standard mode access state different from states which occur during the standard mode of operation, the method comprising: applying a signal corresponding to a non-standard mode access state to the memory system; detecting the non-standard mode access state, causing the memory system to enter the non-standard mode of operation; and setting a control parameter of a flow controller, wherein the flow controller alters the sequencing of the operations and sub-operations executed by the state machine in the standard mode of operation in response to the control parameter, wherein setting a control parameter of a flow controller further comprises: programming a data storage unit which is part of the flow controller with data representing a value of the control parameter comprising inputting data representing the value of the control parameter to the data storage unit, and transferring the input data to a memory device.