Old PTXDIST (64M and 128M only) new Mini2440 (256M)

I'm still using an old version of PTXDIST that only supports the 64MB and
128MB Mini2440. I recently bought a 256M Mini2440 and would like to work on
it without having to use a newer version of PTXDIST.

Will it work if I,

create two new files in the configs directory

platformconfig-NAND-256M.dat
barebox-NAND-256M.config

and update the accordingly?

I tried it but when I select the new platform "ptxdist platform
configs/platform-friendlyarm-mini2440/platformconfig-NAND-256M.dat" I get
the following error:

ptxdist platform
configs/platform-friendlyarm-mini2440/platformconfig-NAND-256M.dat 
error: Couldn't verify that
  'configs/platform-friendlyarm-mini2440/platformconfig-NAND-256M.dat'
  is a valid platformconfig file.
  If you are absolutely sure, please add '--force'
  to ptxdist's parameters, e.g.:

  'ptxdist --force platform
configs/platform-friendlyarm-mini2440/platformconfig-NAND-256M.dat'

The 64 M and 128 M versions differ in the NAND flash layout. That is why
two configurations are required. The 128 M and 256 M NANDs do not differ in
their layout. You can use the 128 M configuration for your 256 M as well.

Ok, thanks.

But is the size of the memory not defined somewhere?

OR 

Shouldn't I define the size of the memory somewhere?

The 64M NAND has another pagesize the NANDs with 128M and above. The total
amount of memory is not important.

@bluscape: What exactly do you mean with 64 M versus 128 M? NAND memory
size or SDRAM memory size?