[U-Boot-Users] Can I write to flash using mw command

[bilahari]

Hi, Jerry,
 
    Took your advice on flash addresses I should put 
into my command sequences with my current flash 
configuration (2 16-bit spansion s29GL064M chips
interleaved to form 32-bit flash system). You pointed me 
to the right direction, thanks. Although I couldnt 
succeed in manual manipulation of flash, I am able to 
do it programatically (I downloaded a free low level driver 
provided by spansion and used it with my code). And it 
works fine, just like u-boot driver (cfi_flash.c). For anyone
interested here is the link
http://www.spansion.com/support/drivers_software/index.html 
     
   But one thing that doesnt work with my code and also 
with u-boot is that if I want to write two different 
values to the same flash locationconsecutively 
( for example when I try to write 0x12 to flash address
0xff000000 and then write 0x34 to same flash address, 
u-boot gives me a message "flash not erased". 
My driver makes the program simply loop forever in a status
register polling loop, I guess).

Is it something natural with flash programming ?. 
Should I always erase the whole sector before I re-program 
a location ? (doesnt sound like a good approach to me), 
is it not possible to write consecutively as with 
the conventional memory?

Thanks for the help and the directions

Bilahari