Tried that "rename Sav to Srm" with mmbn5 TP, It didn't work.

What I wanna know is, why, when It did work for Battle Network 4 Red sun?

In case it’s because of the ROM is incorrect, I’m using a european version of the ROM. Also, just out of curiosity, I did try the same thing with Battle Network 6, and it also worked, so what’s different about 5?