Not enough memory + ISS Problems?

I have also seen the "unable to access memory etc" error while trying to debug on NiosI. I believe this happens whenever the code you have downloaded tries to access (or set a breakpoint) at an address that is not defined as R/W memory in your elf symbol table. For the ISS, it shouldnt really care since its all virtual memory anyway, but I think there has to be a way to re-define or add memory regions, either via the debugger console, or by loading additional symbol tables that overlay the map. I have not figured out how to do this myself so maybe this is all wishful thinking. Any GDB gurus out there?