Squared spines have no place on a survival knife, IMO. They introduce a stress riser into the design which can cause failure (breakage). It is not a coincidence that every single Busse & Kin knife does not have a squared spine…..

Carry a proper striker to use your fire starters with, otherwise use the edge in a pinch. The edge can take it without chipping out, I've verified this with a Taliwhacker and about 20 minutes of blasting a fire steel. It needed a little tune up sharpening but nothing you couldn't handle quickly.