DS Linker EX 16G restoration...

'llo here !
As the title state, i own this faulty linker :
http://ds.jeuxvideo.org/wp-content/blogs.dir/22/files/Brendan/Ds_Linker/dslinker_ex.jpg
It's been 'bout 4 years now it's faulty, but i can't give up
When inserted in my DS Phat, i can see it in the DS menu, but when i want to boot it, i have this message :

Loading menu...
error: not format!

i tried many option to format it (using that DS-USB reader) such as Windows, some other soft (so many); I could format and copy the needed files, but it can't boot.
I've read it should be FAT16. Dunno really.

I've read there are some button combination to boot it in "format mode" but i couldn't get it to work.
So i'm stuck with that faulty device. It could do a somehow fancy USB stick (as i still can format and copy files), but i would prefer to make it work.
The shell is "seperated-unclip" so i can provide pics of the board if needed. 'dunno if i can dream 'bout a possibly chip flash, or anything else.

Thank you for reading, and hopefully helping :