So far as I recall, the fixup replacement cable is a simple, but slightly risky, DIY swap. You should do the searches to confirm what I think has been said, of course.
Apparently, the Ety's are attached to their cables with two small (and therefore fragile) pins. In principle, one would pull the damaged cord off the drivers very carefully using force in line with their cylindrical shape, pulling by the colored part and avoiding all twisting and off-axis motion.
The risky part is that the wrong force might damage the pins and then leave intermittent contact. That would entail a repair out of warranty, and for that reason Etymotic discourages swapping cables on your own. Still, your search of the forums should yield a good many success stories and considerable enthusiasm for the mr. fixup cable.
Seem too ticklish a procedure? Why not just patch your cable with a little silicon rubber from a tube? If none of the wires are broken, that should stabilize things for some time.
Good luck in any case. I'm not the best one to answer because I've never swapped the cables, but sympathy for another Ety used demands that I point you in the right direction to find what you need.