A system and method for automatically saving the contents of volatile memory in a data processing device on power failure. A secondary power supply is provided, which upon failure of the primary power supply supplies power long enough for all modified information stored in volatile memory to be written to a non-volatile memory device such as NAND flash in an AutoSave procedure. In the preferred embodiment modified sectors in volatile memory are flagged, and only modified sectors with a directory list are written to non-volatile memory during the AutoSave procedure.