According to the Epiphany Architecture Reference page 146, for the Epiphany III only bits 0-7 of the MEMPROTECT register are functional. From my understanding, this means that I can set the core to "read only", disallowing writes from other cores (and possibly the host?), but only the Epiphany IV will let me prevent a given core from writing out to other cores, or host memory. I can set all cores to read-only, which will protect them from each other, but there seems to be no way to prevent a core from writing to host memory on the Epiphany III.
I want to experiment with free-for-all execution, where each core basically starts with binary junk, and through successive empirical testing eventually evolve their machine code to do something useful, but this is risky if a core happens to execute a series of instructions that write to host memory. If this happens, the whole board could lock up, or even worse, go unstable via subtle corruption. It needs to be protected because each core is executing random code.
tl;dr is there any way to prevent cores from writing to the host memory on the Parallella with Epiphany III?