Here's a utility that will dump out memory regions from a reb1200 over the ethernet, with the source code included.
Download utility program
Read the included directions.
Remember its a DOS app.
For a good time:
reb12dump fullrom.bin 0 400000
reb12dump dosfat.img 3C0000 40000
use winimage or similar to poke around. Lots of images, and so forth.
reb12dump ramspace.bin F0000000 800000
somewhat of a waste of effort, I'm sure.
Its a little finicky, and there's not too much I can do about that.