weltall wrote:or they corrupt the file system on purpose...
In fact that may well be the key to how it's done, through intentional filesystem corruption of a very specific kind.
Note how each folder of 80mb contains exactly 10 elf files
(in addition to the standard "icon.sys" and its associated icon file)
This hints at the possibility that each of those 20 elf files may in fact be one and the same file, with 10 duplicate (though differently named) directory entries in each of the two special folders. (One each for US and Europe regions)
So instead of 160 mb the total storage space will only be 8mb, since in fact only one elf file has been stored, though that file has a grand total of 20 different directory entries.
Owners of such cards should be able to verify this theory in three different ways.
1: Checking that the precise file size of each of the 20 elfs is identical.
2: Dumping the file contents to other media and comparing the files with a PC program.
3: Checking that a card containing only this firmware has appx 24mb free.
None of the above constitutes definite proof of my theory, but each of those verifications strengthens its validity.
Definite proof would require dumping the entire raw filesystem, and analyzing the directory structures in detail.
Best regards: dlanor