Reprogramming a non-volatile memory system

A non-volatile memory system is provided. The system comprises non-volatile memory divided into a plurality of segments each segment having an address in an address space and wherein at least one of the segments is unused. The system further comprises means for copying any one segment to be reprogrammed into a RAM, the RAM having a size at least equal to the segment size, means for reprogramming the contents of the RAM, means for erasing the unused segment, writing means for writing the reprogrammed code into the at least one unused memory segment, and control means arranged to amend the address space to show the same address of the reprogrammed segment.