Sorry to not respond sooner...this got buried somehow.

No way to do larger buffers now. Not sure about the future. We have developed a flash file system for Do-more which eventually we want to get installed and supported with appropriate utilities. I'm sure that we will do some things to expand the length of data that can be moved once we introduce it.
...however...
Every bit of comm I do to and from the Do-more controller is done with 1K buffers, and I have never developed comm for anything where I used more than that. Where I am moving large blocks of memory, it is always handled as multiple smaller chunks. Even streaming protocols like HTTP that are moving large files are still chunking them on and off the wire.