portapack-mayhem/firmware/application/portapack.cpp

static const portapack::cpld::Config& portapack_cpld_config() {

return (portapack_model() == PortaPackModel::R2_20170522)
    ? portapack::cpld::rev_20170522::config
    : portapack::cpld::**rev_20170522**::config
    ;

}

Backlight* backlight() {

return (portapack_model() == PortaPackModel::R2_20170522)
    ? static_cast<portapack::Backlight*>(&backlight_cat4004)
    : static_cast<portapack::Backlight*>(&backlight_**cat4004**);

}

inside ** is change
one fw so easy to support wm8731 and ak4951 auto detect