Hi Vorticon,
you can comment out the lines 231 & 232 in config.h (#define INCLUDE_SERIAL #define INCLUDE_PRINTER). The SD-interface doesn't have neither a printer nor a serial interface, therefore these modules are not needed for normal operation. They are used for debugging purposes. I wonder, why these modules are activated by default. The Sketch will be reduced to about 28kB after that and an additional advantage is, that the PC-324 can be used at the same time on the Hexbus.
Peter