I wasn't too clear, but I was sort of inferring the same thing.  I think the compliance issue goes beyond Cardbus, though - since it hasn't worked properly on either the 3400 or Kanga either.  I also read there's a potential grounding-wire issue (which could speak specifically to the electrical issues).  I haven't had time yet but i will boot the 5300 off an external and check it out.  I've only been able to reset the PRAM once from among dozens of tries.  It's possible attempting to use the bootlegged battery was affecting that, though.