Modifying a coated knife to strike a firesteel
A firesteel requires a sharp striker. It's possible to use your knife’s blade to make sparks fly, of course, but that can create a dull spot you’ll have to touch up later.
A better solution is to strike the firesteel with the spine of your knife. Many knives (like Bark River) are able to do that right out of the box. On a knife with a "coated" blade, you'll need to remove a small amount of the coating.
Using a small file (a triangular needle file works well), carefully remove the coating from the section of the knife’s spine closest to the handle (circled in the photo). Try to keep the squared profile of the spine -- the idea is to create a bare-metal section with well-defined corners that gets a good "bite" into the firesteel.