C'est quel genre de CPLD/FPGA la grosse puce au milieu ?

Zerosquare" (http://atariage.com/forums/topic/254003-upcoming-jaguar-sd-cartridge/page-47#entry3979294) :
Since your USB D+/D- tracks are pretty long, I'd recommend routing them away from the other tracks if you can, and removing the ground plane near them, like this:
https://electronics.stackexchange.com/questions/203740/extra-spacing-between-some-traces-and-the-ground-plane/203751

Bonne remarque Les pistes vont d'un côté à l'autre de la PCB.