Porous/damaged/bleached hair will soak up non-ammonia, non-peroxide hair color just fine.
You know, when you see kids with the real bright party colors like red or blue or green: they have to bleach that hair first and then put on a vegetable dye like Punky Color in order to get those vibrant colors.
That is an extreme example of how you can color bleached hair with pigmented results. Same goes for the natural shades.
You can try a semi-permanent 6 wk color and it should grab on your eyebrow hair if the hair is porous enough. Or try 5% peroxide with your usual recipe.
There are true dyes (not hair color, but DYE) out there that get darker w every application, usually made specifically for eyebrows and eyelashes.