[Yaffs] flash_eraseall

Hi everybody,

I've an issue concerning the "flash_eraseall" command. In particular I
am simulating a Nand Flash using the module nandim like this:
> modprobe nandsim first_id_byte=0x20 second_id_byte=0xa2
> third_id_byte=0x00 fourth_id_byte=0x15
If, after I mounted the Flash memory and wrote on it putting some
folders and text file, I used the above command (i.e., flash_eraseall
/dev/mtd0 ) then I would expect to find nothing into the memory (as if
it was formatted), but I still have the directory tree and files (and
when I open the latter there is something like <FF><FF> ... ).
Is it normal? What is it due to?
Thank you in advance for your avalaibility.

Best regards,
Salvatore G.