1)Usual suspect from a software perspective for unexpected crashes is memory problems.2)From a hardware perspective, I would suspect power problems.As you did not post schematics or code it's difficult to judge.Any pointers in dmesg as to happens with the port when your device fails?
I've seen USB devices fail in ways that seem to require that the upstream hub be reset (power-cycled) before they re-appear to the host. And those were proper USB hardware, not the V-USB hack (which seems to be less-and-less compatible with hosts as time goes by.)
Hi,very interesting project. But I'm wondering how it was possible to compile the V-USB libraries with the latest Arduino IDE - I will get always errors ... Do you have modified the Arduino V-USB libraries too?