To provide a method for writing to a flash ROM which makes it easy to specify a sector of failure even if writing to the flash ROM ends halfway in failure.
A sector including a progress state recording area 3 is erased and areas other than the progress state recording area 3 are written by a maintenance means 5; and the bit for the sector including the progress state recording area 3 is rewritten from 1 to 0 by using a maintenance means 4 and the contents of the flash ROM 1 are erased in order from the sector and written. When the writing is completed, the bits for sectors in the progress state recording area 3 where the writing is completed are rewritten from 1 to 0 by using the maintenance means 4 to record the state of the writing. Then it is judged whether or not the final sector comes and when not, the same process is repeated.
TAKAHASHI TOMOHIRO
HAYASHI HIDEKI
